Shoulder holster under your riding jacket would be my recommendation. Are you planning on carrying that thing cocked and locked? As far as extra mags go, don't you think throwing 7 or 8 shots of .45ACP at someone is enough? I usually don't carry an extra mag with me.
I have several guns but the easiest one I conceal when I ride is my Ruger .380 LCP, it fits into almost any of my riding jacket pockets.
"Show me a man who makes no mistakes, and I'll show you a man who doesn't do things." Theodore Roosevelt."
2007 Victory Kingpin
Current projects - 1986 VN750 & 1988 EL250