take a look at Allen Morriss' car at his website http://www.smartstoreinc.com/pantera/mirrors.htm
He mounted them without glue by making a stainless triangular shaped piece. He's got pictures and a description of how he did it.
If you still decide to glue, talk to your local windshield pro, one of those mirrors flying off at speed would be a mess
Good Luck
Gary
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