how long are running the clen?? and at what doses??
what kind of BF are we talking?? you should use 1.5 inch for glutes, 1 inch is good for pretty much everywhere else quads, traps, pecs, 5/8-1 inch is ok for delts. but if that is you in your avatar... I wouldn't do pecs with a 1 inch, and I wouldn't use a 5/8 for anything!! you don't want to inject into adipose tissue... you want a deep IM injection!!
if using amps... I personally like to draw with a 25g and inject with a 23 guage... due to passible glass fragments... I just feel safer that way!! I prefer the 23g to inject because I don't have to push on the plunger as hard an it maks for smotther injections!! however if you are using a vial you can draw with a 21-23g I alwasy change out my pins as it also makes for a smoother injection!! even just going through the rubber stopper seems to dull the needle enough that I have to give it a good push which then in turn slams the needle in... which is ok as long as you don't hit a nerve!! if you go in slow when you start to feel you're goin into a nerve you can back it out slightly and redirect it a bit and continue with you injection. anyways hope that helped good luck!!