Biggest problem is continuity of fuel that will carry the fire. The taller the sage, the less grass understory to carry the fire. Viewing a potential burn area from the road across the canopies of the sage plants can be very misleading as to its continuity. You must get out and walk through it. Grazing must frequently be deferred for 2 or 3 years to build enough grass understory to carry a sage fire.
Window of opportunity is just after the snow goes off, before green up.
Treat with a herbicide. Typically, forbs will be the dominant plants after a successful sage burn. Grasses may take several years to crowd out the forbs, unless you seed after the burn. Running the fire into the snow line can be an option. Often tough to get a continuous burn in oak unless wildfire danger is high.