Once again OpenTx has shown itself to be a superbly flexible operating system. As with my F3F setup, a special Calibration mode takes care of left/right symmmetry, while 'high mixing' is used to break the mixing down into manageable chunks. By combining these two techniques, it's possible to design setups which are sophisticated yet straightforward to configure. And as with the F3F setup, key adjustments can be made using knobs and trims, so there's less need to delve into the menus.
The F3J setup runs equally well under OpenTx "classic" and Version 2. More details and download link at OpenTx Clinic.