'TRESO' seem to be very good Nipples by all accounts ( 'The Possibles Shop' may have them in stock ), but, regardless, one still has to find Caps of specific make and Size to fit.
I only have a few .44 Cap & Ball Revolvers, and, Remington No. 10 Caps fit all mine just fine with no fussing.
You might do well to try some smaller Size Caps, and to try different Brands of that size, to find what will be best for your Revolver.
This can be a hassle...for sure.
But once you have it sorted out, you are 'done'.