I've got a vegetable tanned leather desktop whose surface I'd like to harden. It was not treated before being wetted and stretched onto a desk, then rolled with a pin while wet, waxed with beeswax (melted in with a hairdyer) and finally covered with Fiebing's Leather Balsam. While I like the covering, I would like to harden the surface a bit and also see if I can make it a bit more slippery as well.
I've thought about mixing together some carnauba wax with a solvent and applying that, as that would seem to be the hardest wax covering, but perhaps someone here might have a better recommendation for this application. Would removing the Fiebing's layer with saddle soap and applying an alcohol-based hardener work? I've attached a picture of the desktop surface below: