17x7 & 18x7.5 w-40 offset

[KingKole02]

What do you think about the rims size? Does 7 wide sound good? I would like to run 235-45 rubber. Have been searching like crazy but stuck on this info. I have a choice to get 17.7 or 17.8 rims at a 40 offset. Wanted to hear others experiences.
Have search offset on this site but nothing comes up with what is acutally requied, or atleast I haven't found it.

Now looking at 18x7.5 rims because of the 7.5 width.
I understand that the offset is how much the tire will stick out from the axle and 5mm isn't very much.
Have heard that people have problems with rubber on the inside of the strut with rims that are to big and also to wide. Larger you go the thinner is would have to be to fit. Have also seen a PT with 20" all around with a 6" wide rim and thin tires.

At this point I have read about everything I need to know about the rims I'm looking at. I belive that would fit my ride. I hope I can get them per money status.
Thanks