I wouldn't worry about rolling the tires off the rims. My Atlantis has Dyad's and I've ridden up to 2.25 tires and pretty low pressure, never had an issue. Currently running 38mm Barlow Pass tires, desperately trying to wear them out so I can justify the 44mm tires :)
I've also run similar tire setups on HPlusSon TB14 (basically a 23mm wide box section rim) and Archetype rims, never rolled a tire. Even on Mavic Open Pro rims I have had good luck running 32 Challenge Grifo tires for CX races, down to 28 psi, and never rolled a tire.
What frame are you building up??