I've heard some kinda confusing opinions. One is to start with aluminum oxide coarse grits and finish with silicone carbide fine grits. Another is to never use silicone carbide for wood. Aluminum oxide always seems more expensive, if anything can be taken from that. One thing I'm trying to defeat is those tiny scratches that are easily missed until the finish reveals them. I start with no lower than 80, sometimes 100 or 120. Then go 150, 180, and finally 220. I haven't been really paying attention to material or coatings so far, just grits. Having some mixed results, although my technique doesn't always seem to be the problem (could be wrong there). I like bare/dyed wood finishes, so I haven't been adding anything that would really fill and scratches and would be fine under an opaque finish.