Cutting down to lightweight...?

ok, so i am going to be fighting at lightweight for mma. i was wondering what is the typical weight people cut down from. I am 5'9" and weight about 175 right now with 10-12% BF. I was thinking that I would bulk up to 180ish, then cut down to 171 leaving me with 6-8% BF. is 170ish about what most LW cut down to 155? or should i bulk up more and make a harder cut. and yes i know how to cut, i was a wrestler and cut 15 pounds before.