I use 18 for draw, 23 for glut injections. My doctor blew my regular prescription and CVS gave me 23 gauge syringes and wouldn't give me the 18 gauge for draw, even though the prescription on the syringes said to use 18 for draw. I had to do the last two by drawing with the 23 gauge... it's really tough with the oil, but you just have to patiently wait for the oil to slowly trickle through. Most of the time, surprisingly pain free. Still amazed that I do it though... I used to pass out on occasion at the sight of my own blood.

. I guess that's how I knew I was really serious about this. Incidentally, most of the time I don't bleed, but on two occasions, I've hit a surface vessel, which gives a good rivulet of blood initially, but stops in seconds. I've wondered how much of the injection I've lost, if any, when that happens.
I had a hard time sourcing the EV back in October, which kept me on patches a bit longer than I wanted, but have refilled twice without issue now.