I am building a shower enclosure that will have a glass surround. I think the Schluter Curb is too high, and want to cut it down shorter because the travertine tile base board is 4" and the curb is 6". I have already thinsetted it in. Can I cut it down to the correct height and still have it be steady? Also what is the typical thickness of the Ditra after it is thinsetted?