I have been doing shoots for 8 years. My testosterone level when I started was 62. I do 1.0+/-ml every week. Doctor has agreed to keep me on the dose I am now on or higher, we are taking advantage of the no sperm thing as our method of birth control, it has worked great.
I put it in my upper leg, about abeam of the penis, much less painful up high.
I lost one but to cancer and I am a big guy my doctor says though my nut is smaller it is still one of the larger ones he sees. I don’t worry too much about shrinkage I just want zero sperm and that is what I have.