'65 tire fitment questions

[GasserMac]

This question has been asked in different forms before but here goes...I'm looking at a rear set of M & H tires for my '65. They spec at 15", 7.8" tread, 10.3 section width and 26.2" tall. (G60/15) The rims will be 15x7 with 3 3/4-4" backspace. Just removed a set of 14" rims/tires with 4" backspace, 7" tread. They were P23560R 14's and fit pretty good. Aside from the diameters, the specs for the 2 are pretty close. I'd like to fill up the well but not have any rubbing issues. Want to stick to a bias ply and no radials. Have no problem with rolling the fender lips for clearance if need be. Think i'll be o.k.? Any suggestions?
Also, the previous owner used washers to shim out the rear brake drum from rubbing the edge of the brake backing plate. It works but i'd like to go with a more correct fix. Is there a less shallow drum i could use and lose the washers? The washers have about 1/2" of stack on them...If i go with something more narrow and bring the drum in, i may encounter my tires rubbing on the springs requiring wheel spacers to bring them out again. Would that be my less of evils? Hmmm....?
Hope you all had a good Easter....
Thanks, Brian

[alans 64]

here is a tire spreadsheet borrowed from one of the chevy forums. I have used it on my 55 chev build and it works. just fill in the measurments and sizes and get your results.


http://tri-5.chevyrides.com/rear_tire.php

alan