help with wagon please??

I gota roadmaster wagon we are bodydropping. i know you cant really run a 20 up front but i know u can get close. im wanting to run either some 15 or 16 inch smoothies with baby mooms and beauty rings. anyone have any idea what size width and back spacing to get?

also i want a fat white wall. 3 inches or more. where should i look to get a nice deal on some nice tires. ive heard there are some out there with real nice tread patterns. need help bad thou, i dont know shit bout this stuff.

thanks