I've dropped moving the hotend inside the end effector for now.

Raising the pushrod joint to the top of the heatsink didn't work.  No down-force on the inside edge when near the edge of the build area..  It has a new github branch if anyone wants to play around with it.

I was able to reduce the offset by about 1/3rd by moving it up so the hotend flange is up inside the U joint instead of being surface mounted on the bottom.

That was relatively easy.  Added my part cooling fan mount while I was at it.

Printing the new parts.