I use nitinol supper elastic wire, that I bought from:
https://www.ebay.co.uk/itm/222606922773 ... SwO5VeRbg1but I'm sure there are US suppliers. This isn't the same as the 'memory' wire.
You have to shape them by heating to red heat, but not overheat them as you then start oxidising the surface and get a hard, white rough surface. I've been using my wife's kitchen blowtorch! I use 0.4mm or 0.5 mm depending upon the size of the ring and use a simple drill bit as the former for the ring. For most rings, I hold around 4cm of wire with my fishing forceps at each end, heat until the metal becomes plastic then turn it round the smooth end of the drill but to cross over the wire to form the ring. I then clamp the ring in an old, cheap fly tying vice, heat the wire again where the wire crosses over and pull the wire down to form the shape of either a double or single leg guide. I then cut and file down the end of the feet. For the tip ring, I do the same with 5cm of wire and make the shape so there is about 2mm gap. I've tried both crossing over the wire and just leaving a gap, both seem to work. The tip ring is tied simply with the wire down the sides of the tip, with the tip sealed with epoxy adhesive. I've used this tip on a #7 rod and used it for over a year without any problem and no wear on the rings. This reduces the weight of the tip ring by 0.1-0.2g, which doesn't sound much but on an 11ft light rod does make a difference.
It takes a bit of practice to get the rings looking OK, and I've still not managed to get them perfect, but I'm sure those who are more skilled could easily make better rings. For the stripper ring, you really need a larger flame than the one I get with the kitchen torch, so I've been buying the Rec ones. Like the Rec rings, the rings spring back to shape and produce a zing sound as the line whizzes out.
I've got some pictures of early attempts but being new to this site I can't see how to load pictures.