Marty300

I have a set of Cooper SST's in 295/60/20 that I want to put on my 15. Getting 2 1/2 inch motofab level put on end of the week. (then maybe the 3 inch rear kit to bring the rear end up another 1 1/2 inch if it needs it.
I have found some rims at a really good price on sale till this thursday, plus a $40 rebate to boot, online at 4wheelonline.com, but here comes the backspacing and offset questions. Looking to get the tires out to the lip, maybe a little past but dont want the things sticking out too far. They will be replacing factory 18inch wheels and tires also.
Wheel #1 - 375 Warrior: 20x9, 6-135, OS: 0, BS: 4.94
Wheel #2 - 375 Warrior: 20x9, 6-135, OS: 18, BS: 5.65
Wheel #3 - 375 Warrior: 20x9, 6-135, OS: 30, BS: 6.12

This all confuses the hell out of me

Thanks, Marty