As you've figured out, the so-called "stock" size tire is 165r15 but this tire has an aspect ratio of usually 80% which works out to be too tall for most after-market wheels that are wider (5.5").
The only tire that I found acceptable was the 185x65r15. This has a slightly lower profile and helps a bit.
The biggest problem is not actually the wheel width but the wheel off-set. The Ghia has very unforgiving fender clearance tolerances. There's really nothing easy about them especially if you want to run them lowered as well.
You can use a narrowed beam and that would help. You can use those 185x65's in rear and that will help.
The ultimate thing is to use wheels with as much positive offset as you can find (something along the lines of the so called "2 liter" wheels) which place the mounting surface of the wheel at almost the outer wheel lip. This causes the tire to be pushed back inside the fender well and with the lower profile tire you'll get your wishes.
An alternative to newer after-market wheels with positive offset is to try the "marathon" or sometimes called "baja" wheels VW put on the Beetle around 1971. These are 10-spoke, steel wheels which can be color-match painted and with some chrome center caps and lugs they look pretty good and help with the dreaded fender lip clearance issues.
Here's a pic of a Ghia with them and 185x65r15 in rear and weeenie 135's up front: