I prefer 12 week cycles of growth/insulin. Have been doing 3 a year, with 1 month off in between each. Retention of gains and other positive effects of GH seem to be mostly permanent, but then they come on slowly, so patience is required.
My skin is way improved....more elastic, thinner. Most top competitors use GH year round.
You have to remember, though, I am an old guy and see better results than younger lifters.
There is no reason for the 5/2 split other than financial. Doesn't hurt anything either, though. I did this at times just to be sure on the insulin.
Typically, in a 12 week cycle, I will use 4.5iu GH daily the first month, 6iu in the second, and 8 or 9iu in the last month. I start with 10iu daily of humalog and work up to 2 10iu doses, then taper back to 10 at the end. At the same time I taper back the insulin, I'll back off the heavy androgens and go to fina, winny, eq, to finish with a bigger, more ripped look. If you are looking for more mass, one can just keep up the higher insulin dose and androgens to the end....... recently I posted photos of the results each way.