With a single strain gauge in the Hub you can't determine one leg from the other.
Is the power registered at the Hub from the left leg pushing or the right leg pulling.... no way to tell.
You need two strain gauges, one for each leg. No manor of electronic circuit or decombobulatingism will fix a single strain gauge.
Barry
OH.. and yes it's a shame about the Roam.
It's also a shame it's up on Craigslist as we speak!