I would say either the test decanoate found in sustanon or test enethate are the longest acting, If you want to avoid gyno, then why not try a cycle of test prop, injected every 3rd day.
I dont think so either, I know for a fact that prop is gone from my system with in 48 hours, and I have just come off cyp and it was still active in my body 25 days later. Give the guy the real info IG.