Re: HCG mono therapy???
First, I don't really know much about this. You've probably read a ton already, so you probably know a lot more about it than me already.
I think it's pretty striking that hCG can increase estrogen and DHT blood levels (so it's important to get retested for both of these after adjusting to hCG for a few weeks, they say). Estrogen can do a lot of mischief like gynecomastia and DHT causes permanent hair loss. These are some seriously lame potential side effects (that may come with increasing levels of almost any gonadal hormone).
It seems like you're right to question whether the usual recommendation is a level that risks side effects more than you would like. I would certainly tread carefully, and be vigilant of side effects so you can adjust quickly. You don't want side effects to sneak up on you. There's always inertia too. I see many recommend concurrent tamoxifen or letrozole (Nolvadex, Femara, etc.) to prevent DHT/estrogen-induced side effects. It makes me wonder what side effects and/or rebound effects the additional drug(s) might have.
Is your vitamin D level good? T level didn't drop when you quit getting good sunlight, did it by any chance? You probably already knew that vitamin D also increases sex hormone levels? More accurately, vitamin D deficiency causes hypogonadism. (I see this myself by noticing a significant drop in my libido when I don't get enough sunlight.)
A salient thing about vitamin D that I don't see people mention often is that it can also stimulate fungal growth quite potently encouraging myriad fungal infections (skin/ear infections, dandruff, athlete's foot, tinea, digestive yeast, candida, etc.). Since getting an ear infection from one week of 400 IU/day, now I only get vitamin D from sunlight (30 min/day minimum). I think vitamin D from sunlight is distributed better so that it is much less pro-fungal than oral supplements/food additives tend to be. (Or maybe my supplement was just garbage quality. It was cheap. I have not tried another.)
The new research (2012) that says people who live to be older actually tend to have lower levels of vitamin D also seems like higher D (from supplementation) might not be that great. (Or proves the value of moderation & avoiding supplements?)
You seem to like pharmaceuticals, and I respect that, but plant products yucca root and stinging nettle are widely regarded as preventing DHT's effects and they have much less side effects than the drugs that do this. They are both anti-inflammatory and anti-fungal as well. They aren't 5-alpha-reductase inhibitors, though, so they don't cause those weird side effects (like weak erections). (Saw palmetto is a 5-alpha-reductase inhibitor. I don't like it.) I have tried and like yucca root. It does seem to cut down my hair shedding (to nil), and it doesn't cause soft erections (like saw palmetto does).