Hi Daremo, no offence but your calculated FOV variables are a bit off. There is a definite Horiz increase, but there's still some vert loss.
Thanks for testing this so thoroughly! It must've taken a while to make all those screenshots...
You can enter FOV values directly instead of relying on my calculations. I'll happily look into fixing the calculations -- probably after Christmas now though! -- but in the meantime, you can try other values yourself. Let me know if you figure out what the perfect FOV is.
BTW, to answer your other post, you're welcome to upload this to Thief fansites or anywhere else you like, though I guess you'll want to wait for a fixed version first :)