I was tinkering around with a few different things and also suspect the following:
You might not even need to take insulin- a dietary spike may be enough. But I've not really seen any clinical studies or done the tests myself but I don't see any reason why a natural insulin release would be any different to injecting it.
For the best insulin release, a scoop of whey, 1/3rd scoop of egg protein powder, a few grams of leucine and glutamine will spike you're insulin massively (it actually sends me hypo as I low carb diet)
Drinking this, waiting 10 minutes then taking a GHRP SHOULD in hypothesis work very well.
Fats will blunt the insulin release and for best results really you'll want to be taking these without carbs in your system (for optimum fat loss). The leucine will spike your insulin very well (whey and egg protein is very high in leucine) and the glutamine will refill muscle glycogen very effectively (again, whey and egg especially is very high in glutamine peptides)
You can also have 10-15 egg whites and it would do the same trick. Personally I think this is a bit of an effort and not very convenient. Good for breakfast though and very filling and very low in calories.