Ideally, you wouldn't want to use either, so your lipid profile will come back to normal. In the real world however, the best bet is to continue arimidex until you are sure the all the exogenous test is out of your system. Someone said before that letro will cause a more marked uptake of aromatase after it is discontinued but i can't find any references to this, but you maight wnat to consider this...
Also, remember hcg will boost both estradiol and testosterone levels, and an aromatase inhibitor will do nothing to stop this. You have to attack the estrogen receptor itself with nolva or proviron to counter this Personally I like 50mg proviron with hcg, as it seems to offset the psychological effects. Be sure to discontinue this once once start clomid, because proviron is a mild androgen and most likely will not help hpta recovery.