It's great to see that we have serious hobbyists like Tubegroover and JK keeping ancient woodworking skills alive.Some of the juried shows I've attended and judged have had beautiful, original pieces by accountants, lawyers and plumbers. And we've all seen the DIY Utopias built with hand tools in a basement.
The fact is, however, that the skills are ancient and many of the "truths" of today's hobbyists are not in tune with the practices that begin with the Egyptians of the Fourth Dynasty (they invented frame and panel construction)up through the Moors of Spain and to the modern with Sheraton, Chippendale and Hepplewhite.It's like tube design: lot's of variations but all still basically the Williamson amplifier.
As far as finishing and restoration goes, like doctors, conservators try to "do no harm". That means choosing finishes that can be restored (no polyurethane, please)and never disturbing the effects of aging upon the wood.
Audio speakers are a kind of architectural furniture and should be treated with the same care as fine furniture. There would be no reason to strip a complete cabinet to repair a few scratches no matter how deep. Wood develops a patina from exposure to the environment and refinishing should always be done with an eye toward maintaining that. In any case, it's comparatively easy for a craftsman to make an invisible repair to a scratch.
All the products mentioned, including briwax will damage the finish. The Lemon oils, English Leather (?), Pledge, Liquid Gold etc. contain either silicones or alcohol or both and will eventually break down the ability of the finish to maintain it's film. Briwax is a fine wax but the instructions maintain application with fine steel wool which, in the hands of novices, will spread the damaged area by changing the tone of the finish.
In regard to planeing versus sandpaper, there is no controversy. Planing is for smoothing and sandpaper is for leveling the planed surface and opening the pores closed by the plane. Two different functions. If the piece is not much subject to wear, beautiful results can be obtained by waxing or applying lacquer directly to the planed wood. Keep in mind that planing and scraping burnishes the wood and does not allow proper penetration of oil based finishes. When using varnish, linseed or tung oil, the surface must be lightly sanded prior to application. Two part catalysed lacquers will also have difficulty adhering to a burnished surface.
I suppose I've gone too far with all this explanation but I hope it will be useful to speaker builders and scratch repairers. For the scratches, however, taking the speaker to a competent shop will cost no more than a set of NOS tubes. I would be pleased to answer anyone's e-mail questions in regard to finishing, veneering and restoration. You wouldn't believe how beautiful a grungy old speaker cabinet can be made with $10 worth of Naptha and Johnson's Paste Wax. Tune in next week.