Lotsa mis information regarding this,depending on pot size you can easily fit two plants in one pot,this is also dependant on finish size of the plants.
Damm this looks like a bad idea,two plants in one pot,it'll never work,they wont yeild or they'll get sick,the proof's in the pudding peoples,here ya go,two plants per 3 gallon container in pro mix & they budded fantastic with excellent yeild.
I dont do this all the time but if i cut too many clones or too many seedlings become female i dont toss them out,i go two plants to a pot all the time, around 50% of this bud room is two plants per pot.