What is a good size for the stand up ant farm?
Depends on the species you are going to put into it ? Some ants are small, some big, some colonies only go up to 200 workers some to 1.000.000 (or more).
Which are you going to put in ?
Im planning to get a species of Lasius spec. or Crematogaster species.
Well these are rather small ants but the colonies will get big. You could start with some tubes, i always put my new colonies in tubes until they have enough workers to move to a bigger farm.
When the colony reaches about 100 workers i put them in a small y-tong farm. (30*25cm) And when they out grow that i put them in a bigger y-tong. (60*25)
Would a cork nest work?
Yes it could work. Still you need to expand it or let them move to a bigger farm when needed.
alright, ill look into building one, how big would one need to be?
For a small colony (+-100 workers) you could use a y-tong farm from 30*25.
how big for a fully mature colony of lasius?
well that would take years and years to get.. so i really wouldnt worry about a "fully" mature colony.