I just saw that the OP is used to concealing a Glock, and believe some are over-thinking this! I can hide a 5" 1911 easier than I can hide a Glock, even a "baby" Glock. The outside rear corner of a Glock's slide pokes outward, printing against my cover garment, far more than any point on a 1911. This is a combination of the Glock being wider than a 1911, and the rear of the slide, proportionately, protruding farther to the rear of the weapon. The length of the grip, IOW, the height of the weapon from floorplate to rear sight, is not a difficult dimension for me to conceal. When I toted a 1911 daily, up to 2002, I had 31" waist, weighed 165#, at 6' tall. (I have gained about 1" at the waist, and a few pounds, plus am stooped a bit from 6'; it is h-e-11 to get old.)
What did I use to conceal 1911s, for quite a few years? For deepest concealment, I used a G. Wm. Davis Security, an IWB that is very similar to today's Sparks Summer Special II, but with less angle of cant. When using a fuller-cut cover garment, especially with a pattern that camouflaged any bulges, I used a straight-drop Galco Avenger.
I may well return to the 1911 for daily or occasional carry, especially after I retire from policin', and no longer have to tote a P229 or other double-stack auto on the Job. (I prefer to tote only one "family" of autos, for logistical simplicity and consistency of manual of arms.) A bunch of my vintage leather molded while in storage, so my Davis IWB and Galco Avenger may be history; and in any event, the Sparks VM2 has caught my attention, and I have already obtained a Josh Bulman FDS for the 1911, the same rig I presently favor for toting a P229. I do believe, however, that Josh Bulman is hopelessly backlogged, and may have stopped taking orders.
Perhaps I should add that I used really good belts! G. Wm. Davis, Sparks, Kramer, and a locally-purchased elephant hide belt come to mind.