Don't do it. There is an STC for doing this as part of a kit to provide the added strength to the windshield lost from removing the strap. See
www.rtaerospace.com for details. My recollection is that the strap is there for structural reasons, not just to support the compass, and I think that GMAs was a strong advocate of
not taking the strap off. If you do a "Search" on this forum, you might find prior discussion on the subject.
Ernie