Choosing Op-Amp configuration and resistors
For kicks, here is a non-inverting circuit that is not differential, cancels your 1.1V rail, steps +/- 0.81V up to +/- 24V, uses E24 resistors, and assuming the resistors are accurate, incurs 0.4% error on the 1.1k and 30k resistors.

Since the schematic editor does not support tablets, here goes:


run your voltage input to the non inverting input of your op amp. 
run a voltage divider from 24V, through a 22k, 1.1k, to ground. Attach the middle of the divider to the inverting input. 
run a feedback resistor between the output and inverting input of 30k.


But this is not really what you should be doing for a variable bench supply.