Now this discussion is at the right place for a reply. It is my opinion that you need to use the insulin for the entire cycle of GH, for the reason mentioned by AD. Not only are the 2 synergistic, but GH alone will suppress insulin sensitivity to the point of diminishing returns.
I have used insulin in reasonable doses for long periods without difficulty, but I feel, from personal experience, that 12 week insulin/GH cycles are ideal. Put a month off in between, and do your 6 months. I have done three 12 week cycles a year for a long time with very satisfactory results.
I am preparing to experiment with very slow acting insulins in combination with faster ones to maximize the anabolic properties of insulin by keeping a more steady blood serum level. Will report back on that, and thanks to AD for the product recommendations.
AD, you just keep getting better and better!