I personally would avoid the two plants in one pot for several reasons.
First, if you have a issue with one plant, or sickness, it is in the same pot as the other plant. Also, sometimes different pheno's of the same strain might require different amounts of water and different amount of nutrients. Any type of insect infestation will spread quicker, and if you do have to chop one plant early for whatever reason, the others plants rotting roots wont me sitting right next to it.