Slab Floor Boots

DACS

I am looking for a solution to the following problem: Black Max PVC floor boots were set too high before the concrete slab floor was poured. Now when they are cut off at floor level the opening is too wide for standard floor register flanges to cover all of the opening, leaving a small crack visible around the register. The floors are being stained, so there is no floor covering to help obscure the goof up. I have been trying (unsuccessfully) to locate some floor registers with larger flanges to cover over the offending crack. So far, no luck. I have ran into this problem a couple of times. Any one else have any ideas of where such registers might be available?