Maybe this will help, maybe not.
I assume you are asking about a marine head holding tank. We have a 95 H26 with a former owner installed marine head complete with a 20 gal. holding tank, maceator pump, deck pump out and overboard pump out. First of all, I disabled the overboard pump out line! The former owner was one hell of a craftsman as the installation of the holding tank is a work of beauty. The tank is mounted in the closet locker next to the hull and aft of the head. He built a base to support the tank and it uses only the lower 1/2 of the space in this locker. I built shelves into the upper 1/2 of this area and it works great. This 20 gallon size tank will last my wife and I about 7 to 9 days of full time sailing before finding the super sucker. Using the Jabsco wet bowl feature will fill it much sooner. E-mail me if you could use the dimensions for this size tank. I'm in the directory. Ray
