well, while the half-life of Aromasin is relatively short, it's a suicide inhibitor, which means it eliminates the aromatase enzyme completely. to convert test to estrogen, we would actually need aromatase to build back up before it can even convert T to E.... if you look at data on Aromasin, you'll see that while it can lower E by 60% at it's peak, it usually only remains at about 35% lower, due to this mechanism. the key is to keep taking aromasin at the same time, everyday.
anyway, if you are worried about E, then a slightly lower HCG dose is not a bad idea. it is still gonna send a "LH" signal to the testes, albeit slightly weaker.
i'm not a believer in high dose SERMs, at all. there is no data showing that 40 mg of tamoxifen is any more effective than 20 mg, and the half-life is long enough (5 days-ish) that a taper is kinda unnecessary, IMO.
SERMs actually increase estrogen (like HCG does), but simply prevent it from attaching to the receptor. with that being said, we want to raise LH and test, but we don't want it to be so high and so rapid that we start converting more T to E, and then have to deal with it when the SERM is done.