When you stock an aquarium you have to stock for not only adult size of the fish but-territory needs, swimming needs, social needs of that species of fish-not fish in general...it is not a one size fits all....
With this species more fish is not always better in a small space-most times this will not work-small siblings starting out in a too small but heavy planted tank-may or may not work
I do understand what you are saying however, but experience with this species tells us 9 out of 10 times-3 females in a 5g tank will not work long term...its a risky venture......