Just Moved, New Setup Advice

i just moved to a new house and have a basement with 6 ft ceilings. there are bays between the pillars that ar 6W x 6L x 6T. I want to do 2 6x6x6 rooms. The floors are dirt so i am considering just digging holes and placing 5 gallon buckets in them to not lose too much height down there. i usually use tray tables and rockwool cubes but i then lose a bunch of space in height. any suggestions how to maximize the space to its fullest potential. im guessing going back to soil or may be coco. also better to do 2 600's in each 6x6 or are 2 1000's over kill in each. i still have all fans pumps, co2 and everything else from my last grows