A trick I do is to rev to a point - like say your RPM gauge is best for this... a given level of steps per gear - with the lowest gear needing the most concerns - and a level of patience - for the "Distance" the RPM needle revs up, it also must come down.
I did a graphic some time ago to help someone else that had a Manual Fiesta.
I posted it in this thread...
https://www.fordfiesta.org/threads/...g-a-used-2019-fiesta-s-manual.8952/post-24518
'Now, maybe this is a but much to know but the lower end of the shifting - to put the shifter into the next gear without using a clutch - is the key to keeping your syncros...
The keys to this are in the numbers...you can read the manual and it'll tell you focus on the speed to shift into the next gear...
OK, that's great, but who has time these days to read the speedo in traffic when you can
LISTEN to the engine Rev and then make the shift?
Hmm...The best method I found was to bring the 1st Gear revs up to about 2.5K to 3K and easing off the pedal and let the RPM fall down to about 1.5K or 1.9K as your speed drops so will the window to engage the syncro - so the issue really is getting the engines' revs down fast enough in those lower gears (the trick here is this vehicle is a DBW a
Drive By Wire which if you've ever speed shifted a car with a direct-cable to the throttle you used the throttle plate as a means to "grab air" and help the engine find a working load RPM to let your effort in shifting; by either push or pull, and letting the revs the motor does on that syncros effort on the spin of the crankshaft - helps the up or down to find that window.
Unfortunately Fords approach - with DBW the RPMs are "goverened" by the PCM following it's emission profiles so the RPM drop change is different. So dead stop starting takes the longest to shift due to need of the speed up RPM and it's required drop to get up into the next gear for it's range, and then as you gain that speed the Gearing gets closer making the need for "drastic RPM Changes" is far less. It's easier on you to work your way up the RPM scale to finally the higher-end gears like 4th and th5 are shifted with little pulses to the pedals position much like the older cabled throttle is less and less increments of power.
Remember too your forcing this response to the PCM and it's DBW system. So - you know that by feel of the pedal and by the pull-tug or push-engage effort needed to make the transmission go into or come out of gear and into the next one - you know that is what you describe as the "narrow window" - which if you had a cabled throttle plate instead - the air intake you can control to a higher degree to make the engine feather the air to act as a "sponge" so it can work as both the engines' RPM brake and help the syncro use the ability of you to push the syncro and feather the throttle open at the same time to speed the engine up or down to help find that window to engage the syncro and get the gear in.
I know this sounds long, but if you do this on a regular basis - the effort becomes natural and although it is not perfect, the effort is still possible - I do it and it's done by me as an instinct as a reaction to the traffic flow. Takes some time so be gentle - speed shifting can be done quickly and even faster than using the clutch to try and make the spin up or down the gear box needs to make. By using the syncro to do this, with the smaller changes in the RPM to let the gearbox use the syncro, and the RPM you're throttling to up or down to - help the gearbox spin at the right speeds needed to open the window and let the gear mesh.
I also find that FORD IB5 transmission and is B6 style too, use MASSIVE amounts of metal - so switching the gears means that syncro uses itself as the means to force the spin up or down; placing all the torque it has on those gears acting like a brake or centrifuge to spin ALL those gears to make just one gear line up.
I came from a Scion to this, so having the Toyota tranny - I noticed their technology was different but the concepts weren't - so they keep the gearbox light which kept the syncros simpler and having to need less torque to spin up or down - make shifting the whole mess far easier and even after 209,000+ miles - the clutch was still original - so no worries on the clutch side, just the Fords weight of the gears, their mass - affects the way the syncro uses your effort to spin that shaft up or down to mesh that gear you want next.
Have to go, will post more soon...
Adding in...
There are several threads people discuss the changes they want to make to the gearbox, and to be honest, they are all great suggestions but the problem lies in the Engineering needs the maker placed on the car - being mostly the emissions and having enough power to move the car - both Manual and the Automatic side.
Here's one dealing with Tire size and how the output of the gearbox into that Ring and Pinion gearing affects the speed...
https://www.fordfiesta.org/threads/tire-size.9166/post-25442
The Differential (Ring) gear and it's pinion are what I'm talking about. They put a 4.15 to 1 ratio in instead of the Autos 3.8 or 3.7 to 1 gearing on the Pinion to Ring - which RAISES the lower end of the RPM scale in the IB5 gearbox to mesh - so pretty much the speedo is your relative speed indication, but the RPM and shifting the PCM is working the best with, starts at about 1.5K and goes up from there, with the emissions controls, placing the bottom RPM working threshold at about 1,500 RPM for every gear - meaning you can mesh to any gear with it's typical "bump to start" speed of 1,500 RPM for the PCM in programmed to try and drop RPMs to and below that level as long as the Fuel to Air mixtures are not too rich. As you speed shift up in range to the next gear - you'll see the 1.5K RPM mesh part comes up a lot as you drive in moderate traffic and it's speeds (30 - 45MPH as an example) When you rev too high for that gear, you have a harder time letting the RPMs fall to meet the timing needed to the next shfit up window - so the 1.5K RPM shift up drop point seems to work the best.
Putting on the AC and speed shifting - the effect is more pronouced, because the LOADING on the engine the AC makes, drops the RPM faster so using AC might help you gain confidence and help you with the timing-by-feel thresholds more effectively.
Then as you drive normally - the speed shift effort becomes more natural so the need to force the RPM drop wait time, that need, becomes less and less of an issue because you learn to apply and trim out the acceleration in the anticipation of throttle to speed window - then backing off the throttle, pull the stick out, let the RPM drop and push the stick into the next gear - effort and timing becomes more desired simply due to it being easier than to work the clutch and having to tolerate it's grab makes the change in speed almost herky-jerky like the clutch is rusty and grabs too easily.
In fewer words, take it easy and learn the timing by the feel of the stick then work the throttle - on this motor it needs more time to "wind down" due to it's Drive By Wire - trust your instincts - you'll get it - be patient.