My doctor said that pellets are a good option for folks who have been on T for a year with no changes to their reproductive system and who have found a good dose for them that keeps them comfortably within the male reference range for T.
So for someone on T say, 6 months pre-hysterectomy w/BSO, they should wait another 6 months to give pellets a go. For someone like me, 20 months on T and 6 months post-hysterectomy w/BSO, I should wait another 6 months before I give pellets a shot. Because they're a long term means of hormone delivery, you want to be sure that the dosing is spot on. My doctor won't prescribe to anyone under a year on hormones. She may make an exception for the length of time post-hysto if you quickly find the right dose.
There are a few different brands of pellets. Testopel is probably the brand name you're looking at, BioTe is another, and as you said, they can also be prepared by a compounding pharmacy. Because pellets have to be ordered and implanted by a doctor, they are typically covered under the medical side of your health insurance as opposed to under the prescription drug section of your plan. Your doctor should be able to tell you what they can order and inquire with your insurance as to what that would cost. They can often get deals from the pharmaceutical company to offset the cost as well.
I am planning to bring it up at my next doctor visit provided my T levels on my new dose look good. I'm not sure they are, as I'm still experiencing some fatigue. But will definitely let you know what I find out.