To follow up on this in case someone else needs it someday:
I called Jabsco
and spoke to a technical rep. This was a great experience that saved a lot of sweat. I spoke to Mike and he realized with the age of this toilet (mid 80s roughly) that the new joker valve wouldn't work. (one reason I had called.) The old style base as I have uses a discontinued flapper style joker valve. The new style doesn't let what's in the bowl flush very quickly if at all and it fills with water
faster than the flush occurs.
The solution is a new base which also solves my original problem above.
This was my first experience with Jabsco
support and they earned my business in one phone
call. They did a great job and I'm beyond pleasantly surprised.