How many will I need?

[Rainbow_Mumma]

I am going to attempt making pre folds for the twins before they go into MCNs now I want the prefolds to be a good size so that i can use them for boosters later on (apparently you can do this??)
Anyone made theres? How many did you have, was that for 1 baby? Any tips, size recommendations? materials to avoid or whats best?
thanks

[*TripleJ*]

i only have 14 but i also have a couple of fitteds and AI2's so maybe 20 for 1 and i have bamboo ones