Obs is right, run your HCG up until the day you start PCT. it will be there to 'mimic' LH and FSH up until the day your run PCT and start making actual LH and FSH.

As for Proviron. its main benefit is that it has a stronger binding affinity to SHBG (sex hormone binding globulin) then does Testosterone (as well as estrogen for that manner) . so what this does is 'free up' more testosterone into the blood stream. so you essentially get more out of the testosterone that you do have .
its best used on cycle to help provide synergy to your cycle. but being it has little to no effect on LH and FSH, it can also be ran up to PCT to help keep free test levels elevated (there is some debate as to wither it can also be ran in PCT itself to help make the small amount of Test you are producing more effective, and thus limit post cycle muscle loss)