Well, I have the Toyo 45F. That is, I think, an earlier version of your 45C. Everything is interchangeable between our cameras. And, my 90mm is on a flat board (although I always use it with a bag bellows). One note (warning), my bellows are not original. They were remade by Western Bellows in California (nice work too).
I just set it up (normal bellows and 90mm on a flat board). If I really "scrunch" the bellows I can get about 1 inch (25mm) of rise or fall at infinity focus. I can get 25 degree or a touch more of tilt or swing at infinity focus. That is really pushing the bellows, probably best to count on 3/4 those numbers in order to keep your bellows happy over time. Those movements would make "many" landscape shooters happy.
It actually does better than I would have thought!
At the risk of repeating myself, my camera doesn't have original bellows. It too many years ago for me to remember if the original Toyo bellows had more or less movement when pulled together tightly.
Tom