I have a '79 Neptune 24 made by Capital Yachts. My old manual head, wih no holding tank, just died due to a crack in the built-in holding tank. I am looking for recommendations for a new head. I have been looking at an MSD-type head ,as I plan to add pump out and holding tank capacities to it at a later date, but I need the built in holding tank on the bottom for now. I cruise for up to three weeks at a time in the Sea of Cortez with a family of four. With all of this in mind what would you recommend as the best head I could buy (size of tank, reliability/longevity, quality of construction, flushing ability, etc)? Thank you for any and all help.