I've gotten alot of arm growth this past year by spot injecting tren with a little bit of pgf2a (.3cc each pin). The trick is to do it later in the day after an arm workout, and immediatly do alot of light pump sets and stretching. The pump from the pgf will disperse the oil throughout the muscle and help stretch the fascia. Last year my arms were by far my worst bodypart....went back to my old gym last week and kept on getting comments on how much bigger they are now. You can't really do the spot shots for more than 3 weeks, as it does cut into your strength levels on all upper body lifts some (the triceps get so tight and pumped it hard to get your arms over the head for seated french presses). Once I stop there is a slight reduction in size (loss of swelling) but strength comes back in a few weeks and within a few months they are back to the size they were when site injecting. I just switched to doing this on calves....arms is definately more fun, but damn, the calves need some help now.
Oh, I got best results by getting the shot at least 1" deep...with the 5/8" pins the oil would sometimes give a lump appearance that would not move with the muscle. 5/8" of 1/2 pins are fine if it is just pgf2a or pgf2a+water based gear.