> Eventually I taught him how to double-clutch, rev-match when downshifting, and even how to float the shift with no clutch at all.
Most of these things are unnecessary and damaging to a synchronised manual. They aren't saving wear on any part of the transmission. About the only useful application of changing gear without using the clutch when the clutch cable fails.
Unless you are in a manual American truck or a very old British one (the European trucks had synchros). Those are rapidly going to automated transmissions these days in any case.
Most of these things are unnecessary and damaging to a synchronised manual. They aren't saving wear on any part of the transmission. About the only useful application of changing gear without using the clutch when the clutch cable fails.
Unless you are in a manual American truck or a very old British one (the European trucks had synchros). Those are rapidly going to automated transmissions these days in any case.