POT SIZE QUESTION

I'm growing indoor, in a small closet (3ft x 2ft x 8ft) with 800 watts of metal halide light. I want to know if the pots that I'm planning to use, which is 1.5 gallon, would be enough so the plants won't have any problems in a pot this size? Also, the plants are so crowd in there, will I need to worry about the lightning not getting to all the plants or will that much light penetrate through?

Right now, I'm potting 6 plants in 3 gal pots but with this pot I'm only able fit 6 plants. But if I plan to use the 1.5 gal pots then I could fit as many as 8 plants. I need some inputs so I don't mess my next grow up with rootbound in the smaller pots or the lightning not getting through to all the plants since the leaves will all be even more crowded and stacking eachother if 8 are planted. They are stacking as of now even with 6 plants so 8 will give it literally no more room. Thanks

stick with 3 gallon.i think rule of thumb is i gallon per foot of plant.1 foot plant one gal pot 3 footer 3 gal pot etc.