Here's what we started with:
And here's where we ended up:
I copied Jay's idea of cutting an access hole and thru-bolting the toilet down. I still have to make a decorative cover to fill the hole.
Once I got the new toilet installed I found it didn't work properly. It would "flush" but it wouldn't empty the bowl. Flapper valve seemed to be stuck, if I pushed it down I'd get a bunch of air escaping and then it would empty for a few strokes. Now that's a bit frustrating with a brand new head, especially for what the Groco cost! It was also back flooding from the exit hose.
The next morning I talked to Patrick and Groco and pretty much all he said was "joker valve".
I went back and reassembled the joker valve fitting making doubly sure I had it properly oriented, that the fitting was on square and I didn't overtighten the bolts. Voila! It works as advertised!!
I re-used some of the hose clamps when replacing the hoses. As I tightened one of them down SNAP the bolt head came off, failed due to corrosion. Inspected all of them discarding a couple more that looked scary, ordering a bunch of the AWABs next time I talk to Defender.
The clamp that failed didn't look bad but see for yourself: