Max wheel width and height

i would like to know, whats the biggest tire i can fit under my truck and what height? i am keying my torsion bars so the front sits level with the rear, at about the place i had the truck when it was on jack stands and i was taking the engine out. i was thinking of some 18 or 20 inch wheels installed, whats the max height i can go tucked and offset before i start to get some bad rub?

1987 Power Ram 50 4x4

also, whats the lug spacing on a 6 lug? if im not mistaken its 6x130mm lug pattern

Page 2 my man
https://m.imgur.com/a/SqoYJ

thanks! 32" it is

found these wheels here i really like.

also lug pattern is 6x5.5 or 6x139.7 (metric measurment)