rule of thumb is time on equals time off, depends on the person as too how much time do they need off-IE there are people that take more time off than on and when they do come back on they require less to see great gains...
others never come off and still make gains (we call these people Mr. Olympia)
as for the proviron
do a search on this board and you will see what most people's take is, I've never seen anything from it but a lot of people love it