DWC pot size help

This is my first grow, i'm running a DWC and was wondering about my pot size, i figured since the roots were mainly going to be growing out the botton the pot could be relitivly small, is this theory correct???

Sure is!! If you want go 6inch or even 4! I know some people drill holes in the bottom of a 3 or 2 1/2 gallon buckets and place them inside a 5gallon allowing the water to sit several inchs below the buckets or Baskets. Buckets have seem to work best for them, but in my experince I use baskets, unfortionitly its not working as good as using a bucket lol. here are a few pics on basket size made into a lid that fits my 5 gallons. This was my frist run, so my plants look funny thisis a case of lock up