You say you have to have 15 inchers when racing, then you can't have any big brakes in it.
The original reason for the larger wheels was for saloonracing to be able to fit largebrakes within the original outer wheel diameter, therefore the low profile tires. If lowprofile tires was really good why do F1 cars have extremely high profile tires?
The rims themselves, I'll say anything goes. It's up to your personal taste and that is very different among us all.
Personally I like that retrorace look and with 15" and higher profile tires it will be cool.
Will it be like this Swedish classic racer, just restored to its 1970 specs.
Jan