Yep I would also do it sub-Q I don't do GH but when I use HCG I go SQ. Pretty painless, wish they made sline pins that you could swap out the needle on, cause going through the stopper to draw dulls it up pretty good. Maybe they do make em?
You can pull the plunger out and load thru the back of the slin pin.
Ive done that for 1/2 - 3/4cc oil AAS spot shots in areas with very thing skin (My arms, etc).
I drawl it up with a 1" 21ga and fill the slin pin, then gently replace plunger. Sterile of course, dont even breath on it.
Slin Pins are cheap, Ive used two of them for each HCG shot. One to load, then shoot the HCG with the other. Your right, they get VERY DULL
from the rubber stopper.
Transfering increase risk of contamination, but you know what your doing. Ive never had a problem.
A sharp slin pin is much nicer than dull.