Chet:
I did not use that particular style, so my comments may not be worth the keyboard they are being typed on, but consider:
1. Can the pedal assembly be rotated 180 degrees? Wonder if the spacing is different for the mounting bolts on one end compared to the other. If the same, this won't make a difference.
2. Substitute a plain nut rather than wing nut, and use a wrench to tighten. In reality you won't be changing the setting once it is in place and set to your physique, unless some lesser or larger person is permitted to drive it regularly (which I don't advise).
3. I can't tall what pedal support is being used from that picture, but if it is the usual RCR one, can the connection point to that bracket be moved slightly to provide clearance for the wing nuts? I the bracket has two sets of mounting holes; can it be moved to the other set to create clearance?