@VigII posted:Tools were minimal. To cut the circle in the tank tub to mount the boat hatch in, one could use a utility knife but I used a zip tool in my Dremel tool. Just be careful to go only as deep as the tub is thick. I chose a place near the dip tube from the pump above. Push upward to asses the flexation of the tub to be sure nothing is between the tank and tub. Clean up the circle with the knife. I cut shallow enough that I had to cut the insulation with the knife only enough to fold it to the side. Follow the Mopeka instruction and install the sensor trying to choose a place that is as close to perpendicular to the top of the tank as possible, you won't know until the hole is open.
Finish up by installing the boat hatch. Make sure the screws are only long enough to just clear the tub thickness. I ground off the points on the sheet metal screws to be sure they couldn't puncture the fresh tank.
Dave, how about a photo or two for a better idea of the hatch portion of your install.