18x8 rims

Hey guys im having a hard time finding rims for my 89 b2200 I have 2wd sheet metal no body drop. I would like to keep the 6 lug and I currently have 17 eskies. I found a set of rims that im going to get if they will tuck. The front are 18x8 +40 and the ones in the back will be 20x8 +48 offset. The middle is blank so I can get them drilled to the pattern I need. Will these tuck with no problems?

fronts yes...back yes but will be close, may want to trim the lip to be safe

Ok the lip to the outside fender? Also in the rear it should sit alittle further in than the navi rims right? And last question will I have a issue with the innerpart of the bed? Once I buy and drill they are mine so just making sure I know the hieght of a 18 is like a half inch taller than my 17 eskies with 205 40 17 and the 18 having a 21535r18 but the 20 is 2 inches taller overall with a 30 series than the 17 overall will I have a issue with the hieght