brick ledge for a window sill

[peterbrown]

So I watched Allens video in this subject (great) and then made my own with a slight change. I wanted it angled to shed water, so I made it in section with poly solids, and converted to a symbol, then put in my library. Looks ok except the sill is wider than the casing and the ends look funny.

Was I right to make my symbol this way?