Advice asked for widthening rims on a 70 Duster

Jeff, this really isnt the place to cut corners (i know us Dutch guys have a reputation for being cheap, but this is something that needs to be done right)

as people mentioned, forget the 5x100 wheels, its not the same and it will cause issues
(i doubt anyone would notice, but if they would you can kiss you APK goodbye)

there are a few outfits here in the US that will make you custom wheels, but shipping would be a real pain
an outfit called US Mags still makes aluminum rims in 5X4 but again, shipping

i would almost suggest you keep an eye on the for sale section here, stuff pops up from time to time, but remember, "goedkoop is duurkoop"
if it were me, i'd just buy new