Tank size:

How big of a tank will I need for a 3-5 ft. BP? Anybody know?

this has been covered a billion times

but a 30 gallon long would suffice

if u wanted to build
a 4 foot by 2 foot by 16 inch high tank would be great :)

Yes, you can go with 30 gal for now or go with what you will need when the BP is full size - 50 gal.