The length of the needle does not depend on the drug but on the site of application. Locations where the adipose layer is larger, the length should be larger as well.
I use 25mm needles on the quadriceps and shoulders, but I use 30mm needles on the glutes.
Well... the needle gauge yes... this depends on the type of drug. I use 0.7 gauge for aqueous vehicles, 0.8 for oily vehicles and suspensions.
I use 25g, 1in in the glutes/quads. If I shoot just 1cc in a lean area like side delt or pec I can get away with 27g 5/8 in but I am pretty lean in those areas.