No problem halfway, sounds like you have planed it just about like how I did mine.
http://www.hydroponicsonline.com/for...th-system.html
Mine held about 6 gallons of
nutrient solution in it, but because the tote is wide and long, the water level was not deep. I'm not sure what shape your new totes are but I am guessing their about the same as the ones I sure, and/or like they ones your using now. I was thrown off by the term DWC (Deep Water Culture), I don't really consider it deep until the water level is about a foot deep. Good luck with the new system.