I regularly remove pups from G damsii for propagation but the mother plant had not grown any larger for a couple of years now. Similarly with G bruchii.

I don't think G. damsii gets but so big, regardless of whether you remove the pups or not. I was going to remove all my pups, simply to propagate new plants, but then I figured it looked better with all the pups attached to it. Do whatever you like best..
Bill in SC

I think it's at 7-8" diameter now (without pups). What is typical mature size for damsii? Should I reasonably expect it to get any bigger?

Does it bloom again from the same spots, or only from new growth?

Inches or cm? Mine has never grown larger than about 5-6cm.

Inches. It's now in a 12 inch pot. The size seemed large to me to be a damsii based on descriptions I've seen, but for now I will just work with that as the ID because it seems the closest match. One year ago when I potted it up into that pot it was just under six inches across, but it spent most of its energy putting on pups and the flurry of flowers and grown just about an inch or so.

Hence my initial question. The year before it put on about two inches and gave me just one flower. It might be at the point of diminishing returns now and I just wondered if I should try to push for a little more.

I went ahead and stripped most of the pups and repotted. I guess I will see what this damsii's response is in terms of growth and flowers.

{{gwi:462913}}

And on another point, with growth, most of the paint has split and peeled off by itself - no harm done to the plant surface.