No links or studies from me but my personal experience is a few hours IM. I used to do first thing am and post work out but doing post always upset my stomach as a side effect of having carbs too close to gh pin is upset stomach/ the runs... safe to say now I do before I lift and I feel much better!
My stomach issues suddenly came to a stop when I stopped pinning immediately post work out and switched to pre work out. I consumed 100g of carbs immediately post work out as well even tho I knew gh can affect insulin sensitivity. Who knows could be a combo of different things