In my yeshiva, we generally don’t do metzitza bpeh. (Nor mechitza bpeh).
However, if I have a son while this is in force, I will insist the mohel do metzitza bpeh, and I will find anther mohel or do it myself if he won’t.
And no, I won’t sign their ox’s horn either.
If you follow a halachic ruling not to do metzitza bpeh, than the DOH ruling cannot be considured a Gezaras Shmad.