Lots of good advice here. You're being let off easy, by some decent guys!

I will add, that a shaky hand will certainly add to the pip! And, though I've never used a T400 blend, I've heard that it can be a bit more painful. Delts are certainly more painful, for me. Ventro glutes, with a 1" 25g, and upper outer quad, with a 5/8" 25g, are the least painful spots for me.

Don't worry about air in the syringe. Not an issue, with intra muscular injections. I always add .2ml of it, to chase the last if the oil out of the needle.