Whether to use insulin in a GH cycle depends on your goals, and your bodies response to GH. If leanness is more a priority than mass, then you may not want to use insulin.
Unfortunately, GH causes insulin de-sensititivity in most, and you may lose energy and become more lean than you desire, without it. I always use a light dose of insulin just to make sure I get the results I want from that expensive growth hormone.
You should use at least 4.5 to 6 iu GH a day. For best results, use for at least 8 weeks, 12 is better, so you will need approximately 378 iu, or 3 Serostim kits.
Insulin is not all that scary if you take it slow and easy, and do your homework first.
If you were to use 8 to10iu insulin a day, starting at 4 iu after lifting, and working up 1 iu a day, you will get outstanding results with the stack you mentioned.