21G is too large for long term repeated drawing, 23G or smaller should be used. additionally you dont need to use different needles for drawing and injecting (despite popular belief. subq is not better than IM or "more fool-proof", infact subq can be worse for many due to irritation. ideally you would want fixed needle syringes for lowest deadspace, as the vial will last longer.
it should also be noted vials have a shelf life of 2-4 years, so you arent able to stockpile more than that
guess we'll list out ours
1: zzzzzz
2: used to but depression :3
3: :c
4: we use nixos btw
5: awwwrrrufff!!!
6: no
7: :c
8: no
9: no