Box is a perfectly fine group. I've built box rims into my daughter's race bike and their brakes on my son's bmx mini. Nice company to talk with.
When I switched to 1x11 from 2x10 I went from a 22/36 as well and went to a 32t. I changed from an 11-36 to 11-42. The climbing hasn't been a big deal since Long Island is fairly flat but even on the short steep climbs I run out of traction before I need more gear. Either the bike wants to lift up in the front or if i shift weight I spin the tire. Yours is a fat tire so a 46 might be better as it will have more traction and more weight to haul up the hills.