[A/S] Black tank guage locations foir EZ flush instalation

["w9det" <w9det@xxxxxxxx>]

I would like to install an EZ flush system on my black tank on a 27 
ft. 2001 Safari Rear Queen. Seems simple enough.  
Make a trap door on the tank outer casing.
Cut hole near the top of the tank and install seal, hose, etc.
Question: what about the location of the tank guages?
I don't want to drill into the guages.  Does anyone know exactly where 
they are located so I don't drill a home in them.
Campers world has the EZ flush brand.  Any other suguestions.  What 
does Airstream use?