I agree with lowering the test dose and by that amount, and like the idea of adding nandrolone, but I would probably hold off on that right this second, personally. It would be nice to get the TRT dialed in properly first. Or maybe not, 50mg nadrolone would be an almost side effect free dose, and would be something you could run long term with 100mg or so Test, I think. Dealers choice here, I guess lol!
Putting it all together, I think this would be a good protocol for now:
100mg test C per week (50mg every 3.5 days)
25 to 50 mg proviron daily (12.5 to 25mg 2x per day)
500 to 750iu hcg per week (250iu 2 to 3 times per week)
Nandrolone (optional, dosage as @956Vette suggested)
Reasoning looks something like this. You don't need the fast acting Test ester (propionate) anymore. You have been on for a year, so your test from the C and E are where they need to be. The P probably does feel pretty good right after pinning, but that might make some numbers a little peaky. No, it isn't much so you could stick with it if you wanted, I'm just offering my thoughts.
Lower dose proviron should be part of nearly every man's TRT, IMO. Heck, it is used as TRT in Europe, IIRC, or at least was at one time. Like with any oral, you will want to keep an eye on blood work, but 25mg is likely doable for most of us year round.
I've spoken on HCG repeatedly: insurance policy, maintains some functionality, keeps some natural production blah blah blah.
I do like the idea of the nadrolone: I have some in my stash for exactly the purposes @956Vette has suggested. I might not add it right now, but I will definitely give it a shot at some point, and recommend you do the same. The only hesitation I have is getting the TRT numbers dialed in.