Not game to run a FF in front or rear for that matter...feels just a little too flimsy for my taste. Thinking raven front, crow rear on 29rI ran a Racing Ralph 2.25 out back and a 2.4 up front on my 29er SS last year and the combo was great... ran about 28 PSI out back and 33 in front. Ok, so the 28 was a little low (pinch flatted at about 85km) but grip wasn't an issue even on the SS trying to climb up some of those early hills in 33:18.
Unless its been p*ssing down, i'd err on the fast rolling side of the equation - even something like a Furious Fred would work (no centre tread to speak of but side knobs for traction). I'm thinking something like Stan's Raven's would be the gee ohh (crows are just a little 'slick' lookin for me) or perhaps a FF rear, RR front?
Did you run your RR tubeless ? 33:18 ideal gearing ?