I have two 15 gallon boilermakers and am purchasing a 20 gallon third with the intent to build a brutus 10. Has anyone built a similar set up? If so what were the frame dimensions of the brutus? Given the stepped bottom of the boilermakers, 12 inches as specified by Lonnie is too big for the 15 gallon boilermakers to fit on with the stepped bottoms. Does anyone have any suggestions for the size of the cross beams, and how far appart the beams should be from eachother? Should the beams for the 20 gallon be spaced differently than the beams for the 15's? I am just starting the fabrication on the frame, so any help would be much appreciated.