In your position I'd take the "best" two, get them balanced, and fit
them to the front. Then try the truck at 55 and if there was no
noticeable shudder from the rear use it as it is. Many Dodge sized
vehicles suffer from shudder aggrivated by over inflation so check that
you are happy with the tyre (tire?) pressures too.
In Europe one piece Dodge rims are something of a rarity so dont go
throwing them away. I seem to remember one piece rims only on the very
early 3/4 ton WC series, particularly on vehicles NOT going to be used
in combat like my WC53 Carryall. If you weren't so far from Scotland
I'd be interested in them.
((As an aside can contributors indicate which area of the world they
are in if their address doesn't show it, please? Mine is .ac.uk for UK
academic computing, and Todd looks to be in Wyoming, U.S.A. but some
addresses need a bit of help.))