Yes 5 mother plants will give you 100 cuttings but there will not be much of those plants left afterwards.
You can take a clone at around 6 weeks, but if u want 100 cuttings, then i would let it veg for 8-10 weeks so it is bushy enough.
Good Luck.
how big are the mothers? Does not seem unrealistic to get 100 from 5 mothers. When cutting clones, remember to leave new growth below where you take your cutting so it will grow into another branch.