Agreed that 1cm is kind of a lot for FG or SS. If you don't want to respace the rear axle you could change the bottom bracket out and get the crank as close to the frame as it will go without touching, or as was suggested above use chainring spacers to move the ring inboard.

If you can't get it right then using a 3/32 freewheel and chain might help a bit as they are designed to run at an angle whereas 1/8 chains are generally designed to run straight.