I purchased my Blue Tote Direct from Barker Mfg in Kalamazoo. I talked direct to the company. I kinda over-did it youst a little. They had a 42 gallon tote with 10 inch wheels rear/ 8in duals in front and a handle u can hook on the ball of your hitch and pull it to the dumpstation if U so desire for around $200.00 including the shipping.I will check the exact cost if you PM me.
It comes with a little bobber afair so you can see what the level is.
As for auto-matics I think I'd trust the old eyes and the gauge and shut it off myself when its full. I have been able with the 42gallon capacity to dump both black and gray just like I was at the dumpstation. Keep in mind that this is 292 lbs + the tote. Wife and I have been able to haul it on grass by hand,stone in hard ,asphalt is ideal depending on how far away the station is.
It definately beats breakin camp to go to the dumpstation.
Roger & MaryLou
F350 CREWCAB SW LONG BED
7.3 liter Power Stroke Diesel
1977 27ft OVERLANDER
AIR # 22336 TAC- OH-7
May your roads be straight and smooth and may you always have a tailwind!