Weird I was told by a pharmacist who uses to use 18g 1.5" to draw and for glutes use 23g 1.5" and quads 23g 1". I don’t think a .5 is long enough for the glutes. but the above works for me and no pain.
It just depends on how much fat you have. My buddy could probably use quarter inch slin pins in his glutes.
A lot of doctors will reccomend 1.5 inch for glutes because they aren’t talking to someone who is sub %10 body fat.
I can easily use 1 inch in glutes and half inch in my quads and be plenty deep in muscle tissue.