How to adjust a knockoff HT's base ring

My knockoff Nub is right between sizes and it came with four base rings. The biggest ring isn’t small enough to work well, so I had a hard time sliding the cage into the next size down. There was also plenty of pinching along with really painful ball burn, but it felt nearly correct. I read about using hot water to adjust HTs, and here is my method:

1. Measure the ring both vertically and horizontally; I used an inexpensive digital caliper meant for custom cages ($5-$10).
2. Submerge the base ring in boiling water for 10-20 seconds.
3. Remove it and gently stretch it where needed.
4. Check the measurement right away to see how much it has expanded.
5. Place it in ice water (plain cold water didn’t help me).
6. Try wearing it again. It worked for me on the second attempt, gaining about a millimeter horizontally and three mm vertically—pure luck. Now the Nub sits tightly yet comfortably.