yes, that milspec 1911 do get heavy in the sidearmor iwb. never did get attracted to anything smaller than 38 spl.
i am 60; have carried for about 10 years. mostly i keep a couple of pistols (usually one large and one small) in a framed backpack that is always with me.
the small one is often a glock 26 in sidearmor iwb with j-hooks which can be quickly attatch/detatched from the belt and the shirt pulled out a bit and tucked round the butt. crotch holster (e.g. smartcarry) is another alternative, usually with suspenders rather than a belt.
other times the small one is a 5 shot s&w snubby revolver with some plastic coated +p hollowpoints, either in the crotch holster or just slipped into the front pocket.
fwiw the recently aquired smartcarry is sturdy enough but consequently rather stiff. i have an older crotch holster of much thinner material - more comfortable, fine for the snubby, but on the light side for the g-26.