Drill holes in the sides of the pots, not just the bottom, and lift them up on a couple bricks or something to let them drain freely. 30% perlite is fine- just remember tomatoes suck water like crazygonuts and you'll have to check them daily.
I am growing the heirloom 'mortgage lifter' and a commercial variety 'marglobe' this year, along with a striped yellow-and-orange one that I forgot the name of- lightning something... lol.
If you can get an even bigger pot, like a 10 gallon, that would be even better.