Halo extreme is an exogenous anabolic hormone; exogenous anabolic hormones shut down natural testosterone production.... that's why we PCT, and that's what SERMs are for... to re-establish that natural production
If halo extreme "doesn't really affect testicular function" then why would you need to get your test "back up"?
A SERM, Ultra Male, or DAA to promote healthy testosterone production, and if you want, an AI to mitigate any minor estro spikes... any AI would work, E control 2.0 was designed specifically for these types of cycles, tho you could also use adex or aromasin, would just have to get your own dosing right