Sup grower. I grow in a lil 2 ft cab also.
Auto flowers stay small are very easy to grow.
But you can make Most strains stay small but definatly go with the Indicas....
I keep mine extremly close to the lights to prevent stretch tell flower.
Use Topping, and LST to make her into a Bush.
Put soil in a wide/low tub instead of a tall planter for more cab room.
Now the hard part of figuring out how much she will grow when the 12/12 light start. They usually Double for me.
If they want to stretch more I supercrop the stems over to get the canopy even
I flower mine when they get about 8 in tall, 30-45 days veg