You can run the HCG from the start or a few weeks out. Merit to either approach. If you're using prop I would actually suggest starting after the first week because you'll be completely shut down a lot faster.
I'd listen to Dylan's advice. 15 weeks is exceptionally long for prop and completely unnecessary. You will improve recovery time and have just as successful of a cycle - if not more successful - by running the dbol on the front-end and a longer ester test.
Dbol is strong enough to stand on it's own and doesn't need the support of test like other, more mild orals. What Dylan is suggesting is very standard, and it's standard because it works best.
You will probably want more adex while running dbol, but when you're on test only you can probably get away with .25 eod and up it if needed. Just listen to your body.
very well said...