I have a 2009 Georgetown 373 and I looked into getting the SeeLevel gauges.
Due to the odd shape of the tanks in my unit the gauges would never give a true reading and I would have to have a conversion chart.
The free water tank is L shaped with the L hanging over the center rails of the RV.
The black and grey tanks are even weirder. They are taller on the drain side than on the other. They are also T shaped top to bottom to rest on the steel support bracket that goes all around them.
I talked to the manufacturer and they said they expect the tanks to be rectangular for the numbers to be accurate.
I could have handled having a conversion chart but...
They also said the sensor has to be at least 1" away from any metal and with the bracket all the way around the black and grey tanks I couldn't find a place to put them.