I have used the company below to add permanent readers to several mask. The price has gone up, but they do a great job.
https://prescriptiondivemasks.com/produ ... your-mask/
I can see my gauges just fine, but I like to be able to see all the little creatures. I also carry a 10x magnifier lens to look at really little creatures.
The stick on lenses do work, but they are small. I think they are great as a temporary fix and to test what prescription (or how much magnification) you want.
If you have a mask that you are really happy with, this is a good long term investment.
My mask has the "Executive Readers".