FR3 30DS Black tank sensors install?

[DavidMPDK]

This is a question for FR3 owners. Has Anyone installed the Horst sensors in their "BLACK TANK"? If so, how did you reach the top sensor? As you know black tank sensors are notoriously inaccurate. Always reading full. I want to install these sensors, but see a big road block on the top one. If you did this on the "FR3" please show pictures if you can. Thank you. All videos show being installed on the bench or water tank.

[KY25DS]

On my 25DS i can only the bottom of my black water or grey watertank. I would love to add a wash system but cant figure out how to access it. Will be interested in what you find out. I figure stuff like that is best installed prior to assembly of the coach.