Here is a Hotrod magazine article on how to go about it:

Wheel Fitment Magazine Article

You may be able to figure it all out yourself. Or, you could call some local tire shops to see if any of them could help you directly or suggest some shop nearby (or in the nearest major city) of where to find a Tire & Wheel shop that fits and sells Custom Aftermarket Wheels.

Your local Goodyear, Firestone or Les Schwab tire centers might be a place to start. You could look for a shop in Walla Walla, Lewiston, or up North in Spokane.

You could also look for a local Hotrod / Performance Automotive builders shop for advice.