Well don't get them from JP Cycles.I bought some there and they are worse than what you have stock.Took them off after 2 weeks and I was pissed because they looked like nice skull mirrors.
I had the same problem (both loose and not quite far enough out to get past my shoulders). I tried all kinds of things to "glue" them into place, but eventually they
would break loose from vibration or just someone hitting them. Ended up buying some HD mirrors (about $35.00). The other prblem fixed itself when I went to some 12" mini apes.