May not be stiff for your weight, depends on whether you ride the tight stuff or the fast stuff. Also depends on whether you are doing any valve rework in the forks.
As far as jetting, I have a Gnarly Desert with stock silencer, and live at 5280 ft., riding to 8-9000 ft. I am starting with a 140 main (bought the bike totally stock with a 142, and it was SPLOOGY rich - had good success with a 138, ran cleanly prior to the pipe change) and stock needle on 2nd from top clip. I may need to move the clip to the middle, maybe not. Seems pretty good for now, but it's not hot here right now so that may change. But it is a start. The pipe might want a richer main than what you were running before, by an increment or two.