Agreed, I would opt for a nutrient partitioner.
Insulin will only promote fat storage. Insulin does work great for muscle gains, but only when the proper tools are in place. To utilize insulin without gaining fat, one must be taking a decent amount of gh along with it. With that being said, insulin is not taken for the direct mass building affect, but rather to offset the hyperglycemia associated with higher doses of gh.
Insulin + aas provides very little, but when coupled with gh, it has a synergistic effect to exacerbate the igf conversion that gh goes through in the liver.
Mike