Lend me your brains

I heard someone mention you could use a tandem crank on the left to avoid the reverse threading issues.

I actually thought about this, but I have a couple of other fairly simple ideas to fix the pedal against unscrewing.

Do those gear ratios give you the same chainring--sprocket distance on each side? Aka will your hub be straight. I'm sure you've already thought this through and I'm too tired to work it out.

People ride differing chain ring/cog set ups all the time, they just adjust the chain length to fit.