Like many posted here it can be ran the whole duration, or at the 2nd half of cycle. I run it the whole time, I love the stuff.. If you have Human Grade Proviron, all you need is 50mgs to do the trick. 100mgs you'll feel more harder and tight, but not really needed, 50mgs will do just fine. I have a nice stash of it, no joke. I use it with every cycle. As far as your free test comment, in test and studies you'll find that it does just that with nature levels, how ever when your using above TRT levels and 500mgs and greater, the test is already free in your blood my friend. lol
Proviron is the oral version of Mast, that's all.
Also, do not use it PCT, it will keep you keep you shut down, regardless of what people tell you, this is a DHT compound, thus it will hinder recovery. Use when ON, not PCT. Just wanted to put that out there!