Rims for Willys Jeepster Hubcaps

I have a repowered 1950 Jeepster that currently has aftermarket chrome rims and tires. I am changing this back to the factory look of steel wheels and Willys hubcaps. I have the springs and reproduction hubcaps, but would like some assistance in the rim type to use. The rims need to be 5 x 4 1/2" bolt, 15" diameter and probably 7 or 8 inch. I believe that if I use a rim with a 10 1/4" "shoulder" that I can rivet the springs and mate the hubcap to fit. I am not sure how tight the springs need to be - some geometry would be helpful. Also, what sort of tool should be used to fasten the spring rivits? Will also be replacing the tires with a more stock look wide whitewall.

Thanks,
Ralph Genseal