Bent Fork

I have recently re-acquired a Trek single track 930.  It has rigid front
forks with on arm bent.  Deflection is approximately 1".  Which is better;
moving the front backwards and the back forwards to split the difference,
moving the front one back to match the trailing one, or moving the trailing
one back forward again?

I think bending the same fork twice is not the best idea.  I am leaning
towards moving the unbent fork back.  This would not stress the bent side
anymore and it would give me a slightly shorter wheelbase.

I would highly recommend replacing the fork. A steel replacement fork will not cost you that much, and it's money well spent considering that you can alter the handling of the bike by bending the blades of the fork. Peace of mind in this case is simply not worth the gamble of repairing a bent fork. Bending the fork to alter the length of the wheel base is not a good idea at all, not only will you cause metal fatigue in the fork blades, which could lead to catastrophic failure, but you are also messing with the trail, ie how the bike handles.