Add gussets at bends, or put the offset at the pedal pivot mount.
I'd thought of gusseting the pedal end, but the booster end may be a problem. The "S" bend curves up and over the transmission crossmember. Allowing for the rod travel, there is not much room left for a meaningful gusset.
The pedal is an off-the-shelf Speedway unit that already has 1-3/4" offset built in. It would be perfect on it's own if I did not need a booster.