sure, 1" is good for site injections, but 20g site injections - ow ..... I've been using 25g for biceps, triceps, delt and pec shots, been working fine...
It's really up to you, I don't know that I'd be hitting site injections with 20g needles... 1" is a little short for glute injections unless you have a very skinny ass...
Same here YUM, I used 25G 1" pins for my thighs and it worked fine for me. I also used them in my bicep a few times when my thights started to get soar but I did not go in all the way. I have read that some guys use 5/8ths in their chest, delts and biceps too..............just food for thought.
Aikido