Am considering a holding tank redo on my OD34 which would include a larger tank. Seems that all tanks have the discharge on the side near the bottom as opposed to directly out the bottom - leaves a gallon or 2 in the tank. Pretty sure dimensions would allow a discharge directly out the bottom. Good idea or is there a problem with this? Given that I may not find the size/shape I'd really like as a standard, how about custom welded poly tanks? Industry uses these all the time for very nasty stuff - can get any wall thickness, fitting location, etc. Thanks for your input.