You only used so many seed coz you were Testing it out for indoor.....so you weren't sure how many would be Optimum Indoors under light.
Now Airpots have declared a 4 Spot with their pot divider............use it as a Model.....
....
I Wonder how many people we'll see do it now the Kit is available......
....IMO.....I wouldn't Use the divider though........I Think part of what mixed pots enjoy is the mixed roots....the divider would Stop that....
Could be Wrong though.....