71 Cheyenne suspension/wheel info

[spdrcr29]

Ok, so this is my first post, and I'm already asking questions that require alot of work from those who respond.
I have a 71 Cheyenne (my third 71-72, but the first with leafs), and I plan to run 20" rims, and possibly a very mild drop. Tire size is my problem. Currently, the size is 235/75/15. The "plus 5" size is 275/45/20, but those tires are almost a full inch taller according to everything I've read. I was looking at 255/35/20 and 275/40/20 as potential sizes, but am being told by a pair of local shops that the 255 is a "car tire", and the difference between the 275/45 and 275/40 don't actually amount to an inch when mounted on a 8.5 inch rim.

I'd really appreciate anyone with pics of any of the above sizes on their trucks to post a pic with the size/drop info.

The other question is: Are shackles going to give me an 1.5 or 2" drop without sacrificing alot of ride quality? Or, should I use re-arched leafs, or the front hangers? I'm not trying to get a wild drop, because I'll be towing a boat and a bike trailer a couple times a year, but I would like it to be about 2 shorter in the back, and about 1" shorter in the front (simple... coils). The truck was optioned with rear leaf springs.

Thanks,
Ray



1971 Cheyenne, LS-9 pkg, factory air, 350, factory "posi", etc, and it was the previous owner that forgot about the factory paint combo and doused it in red.