I suggest that you use as much as you can afford for your initial exoGH cycle. Body composition changes are subtle and take a considerable amount of time on light GH doses. 4iu or less is good for maintaining your results once you are where you want to be.
To put it in perspective, the average younger man produces the equivalent of .5 to 1.5iu per day of endoGH. Some suppression takes place with Gh injections, so to see obvious results in 12 weeks, 4iu or more would be ideal.
My first usage was 16 weeks, 4/6/8/12iu pyramid over the 4 months. I've done well with 4 or less ever since.