Originally Posted by
chas58
its fine, although in your boat I do put a 38mm in the rear and a 40mm (or larger) in the front.
For gravel, you should probably be in the 35-40psi range and tubless. No worries there. I find going much bigger just adds weight and makes my bike handle like my mountain bike. Nothing wrong with going bigger if you need the flotation or cush, I just personally find 38-40mm to be the sweet spot between acceleration, speed, and traction comfort. YMMV.
Enjoy the bike!
With regards to the staggered sizes from front to back, is it important for each tire to be of similar tread type or can they be different?