You can start HCG as soon as wk 1 of the cycle. I have never seen a problem with guys ever finding that their response lessened over time. It has been talked about online, but I have never seen it happen. A good dose of 250-500iu EW, split into 2 doses, then stopped 3 days out from PCT
As for adex, .5mg EOD is a good place to start. See how you respond and then adjust from there as needed