You can use normal vacuum pedals with hydroboost (and vice versa) in at least 3 ways:
1) drill a new hole and use a new pin in the hydroboost spot
2) get a set of pedals with both holes (like mine) and move the pin (thanks to
@sweetk30 for pointing this option out)
3) swap your existing automatic pedal into the manual pedal bracket and cut it off to be the appropriate size (this is what I ended up doing).
The pivot distance isn't hugely different. It might work out well enough just using the "wrong" location (just guessing, I haven't tried this). You'd have less leverage and shorter travel if you used vacuum pedals on a hydroboost truck.
Aside from the pin location, the pedals are dimensionally identical, so they can be swapped back and forth. Hydroboost pedals come with a return spring and a little cover. I swapped this across with no issues. As detailed in the pictures, 2 of the 4 studs on the pedal bracket are reversed for hydroboost trucks (no idea why).