1 down in the front is very close to going up 3 in the back (like around 2.5 i think)
where do you do most of your riding-my bike is geared for the dragstrip, and short 10-15 min freeway trips dont bother me, and im rarely on the freeway.
if you commute, id suggest against going 1down and 2up. my opinion.
maybe just drop one in the front, that mite give u the extra get-up you're lookin for. think the 636's have 525 stock, but i dont remember
theres a formula and chart-cant find it, google it, that can tell you how much higher your rpms will increase as you change sprockets. or u can do the lame math, but i suggest you find that chart online. maybe vortex' website