HCG & Clomid should take care of any drop of in gains afterwards.
Suspension is fast acting and I believe HPTA levels can START to drop after only days(4??).
The AVERAGE (male) persons body produces about 12mg test a day, so 50mg would be enough to START to shut it down, it is 4 times the amount of what your body use to running on.
Dont know it you would be completely shut down after 3 weeks though.