Yeah, last time I wore one of my 3" knit ties I asked in MC about knots that might be smaller than a FIH. I didn't get any good suggestions. The photo you quoted above actually shows a FIH knot but it looks like the size of a windsor just because there is no taper to that tie. I may have to just get thinner knit ties but I'll check out the Kent knot you're talking about next time.
On other ties, I've always defaulted to the windsor knot because, having a smaller neck, there is no way to tie a FIH without the tie being way too long. But I also think the windsor is a generally better-looking knot anyway.
I never use the symmetrical half-windsor though.
Warning: Spoiler! (Click to show)
So this turned out to be pretty good advice:
Coincidently, I wore a knit tie today, too young padawan.
If you feel the tie knot itself is too long, given that knit ties don't taper, you can fold over a third (or half) of the tie width when going around in front of the back blade.
This knit is 8cm wide and the resulting knot is less than 5cm in height, due to advanced knottery, instead of 8cm.
Again visualised in this sketch. I believe to remember you having German ancestry/relatives so you should be able to figure out what's going on here.
Don't forget to dimple.
PS: if your regular ties are too long for the four in hand, give the double four in hand a try rather than the windsor knots. Remember, Windsor knots are the mark of a cad according to James Bond.