Gh is fine imo. Not really needed but don't see it hurting per se. 400/week to gain 10 solid pounds is doable. Depends how close you are to your maximum genetically speaking. At some point you won't hold on to much more after a cycle as you'll hit your maximum natural potential. Then you'll just yo-yo going up and down. Just do the best you can and reap the benefits. 10 solid pounds is quite a lot of mass. 5 is still pretty decent. Also gotta factor in that the way you look can look drastically different with just a few pounds when lean. So if you're going for a look, definitely don't watch the scale too much and don't focus on some artibrary number you want to reach. Push until you get to where you want to be in the mirror.