You can probably get away with 60mm/2.35".
And the easiest 1x setup is sram. I'm running x7.2 RD and gx 10-speed shifter on one of my bikes. Totally painless to setup.
Be sure to get a NW-chainring though or get ready to but your chain back on all the time.
You got a build thread or any details on the 1x set up? I already have a wheelset with SP dyno hub on Stans Crest rims.