How about two mns? Then you both win!
John, paradoxically, seems more established than
Gabriel, even though
Gabriel is more fashionable at the moment and
John is in decline. Or maybe it's achieved a bounce? I'd use
John over
Gabriel any time, for family reasons and also, though I'm as partial to archangels as the next person, a name that shortens naturally to
Gay seems unwise. And
Gabe just is unattractive! However, I'm well aware that this is meaningless for a mn, so either would do and I continue to favour
John in loving memory of my Great-Uncle
Jack!