We have a 2004 Designer Medallion 29 RLTS, and it has the black tank at the front, then the shower and lavatory grey tank, and the kitchen sink grey is toward the rear. Fresh water is all the way in the back. Not sure of the floor plan of your 2730, but it might be similar. I got schematics of the drain system emailed to me from Jayco on request, and it appears that the drain from the shower/lavatory grey tank ties into the pipe from the black tank, which functions as a first rinse, and the drain from the kitchen sink ties into the pipe further down the line, which becomes a second rinse. Black tank is supposed to be 54 gallons, and grey tanks are 35 gallons each. I would suggest that you email Jayco and ask your specific questions, and they will email you back in 2-3 days with the info they have available. Hope this helps.
2003 Ford F-350 V-10 Crew Cab 4WD Long Bed
2004 Jayco Designer Medallion 29 RLTS 5th wheel
Bill, Gayle, and Mindi (dachshund)
Retired at last !
Nothing is foolproof to a sufficiently talented fool.