Thanks to all of you for your advice re: shoulder holsters. I have decided on the Miami Classic. A little place in Irving, Texas ( http://www.aactionsports.com/Galco/index.htm
) sells the Miami Classic Shoulder System for $92.25 (regardless of revolver or pistol model). Their web site did not show a holster for the particular Glock model that I have so I contacted them and they ordered the holster for my model at no extra cost. I picked it up on Friday and spent about an hour this morning making the initial adjustments. I will probably tweak it more after I have worn it for awhile.
ProSouth, you answered one question I also had. In the brochure that came with the holster, optional tie down straps for the holster and mag carrier were mentioned and I wondered if they were needed.
I was also surprised that the thumb break on the holster is on the "body side" of the holster rather than on the "arm side."
After using a Kydex IWB holster, the leather really seems to grip the Glock. I have adjusted the holster's tension screw as much as possible and I suppose the tightness will loosen somewhat after some wear.
As a novice with a shoulder holster, any other advice that you care to offer will be welcomed.