Wheel size, El camino. Help pls
 

Im looking at buying a set of 20x10's for the rear of my '64 El camino. Wheels have a 6.25 back spacing and positive 20mm offset. I've done some measurements and they seem to fit. Can anyone confirm this please. Would like to fit a 285 or 295 on there. not sure on profile.
I know u guys are not keen on 20's over there but it is over here down under ;]