Okay, here's the thing with insulin... For starters, you don't want to be on it without HGH. It is definitely one of the kings of anabolic hormones, but at the same time, it does preferentially cause fat storage on its own. The real key to using insulin to really grow isn't so much insulin itself but how it works in conjunction with a couple of other hormones. We understand and accept that IGF-1 is awesome for building muscle, but the reason you want HGH while you're using insulin is very particular. HGH has an effect on thyroid hormone production and causes the conversion of T4 to T3 to increase. IGF-1 does not have the same effect. (IGF-1 causes fat loss through a different mechanism.) HGH turns on lipolytic action in adipose tissue while there are no receptors for IGF-1 in adipose tissue. This is why you need HGH with insulin. The fat loss effect through increased T3 production and increased lipolysis allows you to take in more calories to build into lean mass while burning fat stores at the same time. The real key to using these components correctly however is realize that your body only has a limited amount of T4 to turn into T3. This means that this fat loss/muscle gain effect will slow down and stop after a few weeks as your T4 stores are depleted. To combat this, you must supplement with T4 to continue supplying the conversion to T3. This last step is crucial to the process and leaving it out is why many don't get the best gains with their HGH/insulin cycles.
As for my personal experience, sadly, I didn't know any of this when I attempted my cycles of insulin. I always seemed to have either HGH or I had insulin and couldn't seem to get them both at the same time. I used Humalog for my cycles, worked my way up to 12iu/day. Ended up gaining both muscle and fat but not a lot of either. (I didn't know of the availability of Humulin being over the counter at the time.) Only now having been recently diagnosed with a genetic disorder, hemochromatosis, I've had to start supplementing with T3 due to hypothyroid effects, and it was my research on thyroid and its relationship with HGH where I found the above information. I also have an Rx for T4. Due to my IGF-1 levels going low, I'll be seeing a doctor shortly about an Rx for HGH. I hope to get an Rx and then be able to have all the components in place.