OP, it is probably not a good idea to take finasteride on cycle.
Even if you control your estrogen with an AI, you still need androgens at the breast to inhibit gyno. The fin will decrease test to DHT conversion, and DHT being 4 times more potent than test, that will decrease the total androgenic activity in your breasts big time.
It will get even worse if you add more non-test exogenous stuff like anavar. That stuff will suppress your endogenous test and many of those substances are more anabolic than test but not as androgenic, so you get less androgenic activity at your breast through this channel too.