I would use a SERM before I thought of using anything else, and personally I would always use a serm in any post cycle therapy of any hormonal product. If you're using it in conjuntion with other things (like the NHA stack, etc), I would just research the proper dosing protocol. You don't want to limit your estrogen too much.
Activate in the NHA is great in pct with a serm so I've read, just watch your dosing...if you shut your estrogen out too much then you're going to suffer from it (super low libido and you're going to feel real sh!tty). I'm looking into this myself atm since I'm adding a JW/BAM/Restore stack to my pct along with nolvadex. Basically I'm timing everything right though so that my restore only overlaps the final part of my pct but this is a totally different stack than yours.