just measure with syringes. is what I do. no drops, just mls
I have syringes that measure, fully filled:
-1ml
-5ml
-10ml
-20ml
and they're all numbered in fractions accordingly (like, the 1ml syringe is numbers in 1/10s, with 1/100s noted with lines; the 10ml is numbered in mls, with 1/10s noted in lines, etc)