When I used to pin glutes, I only ever used 20g and on occasion I would find that I have PIP, but not from the size of the needle ... but from injecting the Cyp or Enan too fast.
Since I started pinning delts, I had ONE look at the size of a 20g and my delt ... not if I can help it will I EVER pin my delts with a 20g ... since moved to 23g ... might just shift to 25 soon enough.