I would inject both IM as you will consistently get higher peaks. It does not matter where you inject as both will have a systemic effect. It will not site enhance muscles. Just inject into a muscle that has little fat, since you are using a 1/2in insulin pin and want to get the shot into the muscle. I use delts and tri's. It does not matter if you inject gh or IGF with or without carbs. These are exogenous drugs and will effect your body regardless of insulin levels.
For injections, it depends how much GH you are doing. If you are using 2iu, I would take it all at once, right before training. With 3 or more IU, I would personally split the dose up into 2 shots, first thing in the AM and pre workout. With IGF, I would specifically use IGF-LR3 and I would inject right before training. I would run 30mcg for 3 wks. 60mcg for 3 wks. Then 3 wks off. Then repeat.