No such thing as a stupid question really, everybody on here did not know the answer to that question at some point
Kimber Ultra line of 1911s use compact grips.
Kimber Pro models and 5" models 1911s use full size grips.
By and large (and there are indeed exceptions) on 1911s
5" or greater barrel = full size grips
4" - 5" barrel = full size grips
3" barrel = compact grips
Also check out Alumagrips, VZ grips, Houge grips sites. Wilson Combat makes a nice wood grip as well, while there check out some really nice 1911s
Good point brought out above on the grip thickness. I prefer the standard grips but some like the think grips.
Welcome to the wonderful world of 1911s, you joined on the 100th B-Day year no less