rode a 100k gravel event today on my 32mm cx tires. some larger tires could have made it a softer ride. i feel pretty beat up, even though most of the gravel was hard-packed and tame. so it was fine, but a little more volume would have been nice.
I acquired a 38mm G-One for a rear tire, which is the fattest thing that will fit in there. Just need to pick a front tire.