Yes, you're right with the information you found.
As for wheel size, anything from 13"-17" will fit, dependant on the size of the brakes.
IIRC, I think the smallest an 8v gti can get is 14", they need about a 60 profile tyre, so they will look 'balloony'.
17s will look ridiculous.
I'd say 15s are best for a mk2, 16s can look really good too, take Mr. Blue's as an example
