It looks like the key is to get cages that have no tab. The tab is the part of standard cages that hooks onto the back of standard bottles (in their indentation). Perusing all of VO's cages, they show/recommend a couple different ones for cylindrical bottles. All of them are made of maleable steel, for to improve the fit for each bottle
Incidentally, the part of my Punc bottle that broke - the cap - just happens to match the threading of Klean Kanteen caps. So now I can keep using this bottle (which fits standard cages). I will still be getting new bottles and cages though, since I need additional ones and with larger capacities.
Thanks to all for your input. TnMSN, that's a great way you have for adjusting the fit of the bottles. Innertube pieces + electrical tape.