500W? what light is that one?

2 plants per pot is never a good idea unless you are in seedling cycle. Once they get older and start to sex you have a greater chance of one being male (nature has a way of working out how to survive).

Then you need to catch it at the right time or you can have hermies or worse yet your female plant can do to seed quick.

The choice is up to you dude that is my opinion.