I found the following tire combos to be a good mix between rolling resistance and traction for my two 29ers mounted tubeless on ZTR Arches.
Rigid SS 29er (Emphasis on reasonable lightness, good mashing traction, and decent volume):
Front: WTB Weirwolf LT 2.55 @ 18 PSI
Rear: Maxxis Aspen 2.10 @ 23 PSI
FS geared 29er (Emphasis on stable cornering at speed, good braking/pedaling traction, decent sidewall and tread durability, and burp resistance):
Front: Rampage 2.35 @ 22 PSI
Rear: Specialized Captain Control 2.2 2Bliss @ 28 PSI
Rigid SS 29er (Emphasis on reasonable lightness, good mashing traction, and decent volume):
Front: WTB Weirwolf LT 2.55 @ 18 PSI
Rear: Maxxis Aspen 2.10 @ 23 PSI
FS geared 29er (Emphasis on stable cornering at speed, good braking/pedaling traction, decent sidewall and tread durability, and burp resistance):
Front: Rampage 2.35 @ 22 PSI
Rear: Specialized Captain Control 2.2 2Bliss @ 28 PSI