Just for completeness, but not sure if required - A20 is available from Pin 15 of U28 on the Rejuvenator. I wasn't sure if the 2MB jumper was for that or for other logic to the DRAM bank (since it goes from the 256k x 4 DIPs to the 1M x 4 DIPs or SOJs in every 2nd slot).
Well, it isn't confidence I lack - more like good eyesight and a steady hand