I've heard 18 gauge can sometimes rip out tiny chunks of rubber from the vial lid, anyone had that happen? I just use 23 gauge for drawing and then a fresh 23 gauge for injecting.
Nope, I put oil-based through a 29g slin pin all the time, as long as you warm it up it only takes about 10-15 seconds for 1cc. I use 25g for quads and glutes, 29g everywhere else.
We're all afraid of the unknown. Practice on an orange to become familiar with the use of the syringe and needle. I use the same 22g needle to draw and inject and it doesn't hurt. The only hurt or soreness comes afterword.
Be sure the needle is tight.
I keep some toilet paper handy to use as soon as the needle is pulled out in case of bleeding. Looking forward for your post injection post!