I did a 4-month, low-dose (20mg), 3on/4off SD pulse (at the low dosing, it just took that long to get through a bottle). It was very successful (put on 15+ lbs LBM), and I experienced zero shutdown (continued to "perform" magnificently right through the end).
With the lack of shutdown, I figured I could get along with 6oxoExtreme as my PCT. I tapered it down gradually for 24 days, and everything was great, right through the end of PCT. But then...
I woke up 2 weeks post-PCT with a single, swollen, painful, lactating teet. Typical SD "delayed gyno." Sux ass.
Needing to act immediately (meaning OTC), I ran out and picked up some Novedex XT (contains ATD, a very potent oral AI), p5p (to halt the lactation), and NicoDerm patches (nicotine is a milder AI, and you can apply the patches directly on the nip). It worked immediately and spectacularly -- the pain and lactation stopped within 2 days, and the swelling was wiped out within a week. (I'm not sure I can even feel the gland under there anymore. Yay.)
Actually, the 6oxoExtreme seemed to work just fine as a solo PCT. I think I simply needed to stay on it longer than 24 days for a 4-month cycle (even though it was a low-dose pulse cycle). So now I'm staying on the ATD/p5p much longer -- approx 12 weeks, with a very very gradual down taper (hoping to avoid a 2nd bout of e-rebound). And I've ditched the nicotine patches -- they may have helped, but they're no longer needed (and they can give you a rash, applying them to the same spot day after day after day).
I'm very interested to see how your OTC PCT approach pans out. Good luck.