Hello; some points:
-you never ever put wax on a ding due to is better water inside than grease. Then the ding will be transformed x times bigger to get rid of the grease and fungus when is too old.
-you never sand to get rid of shatters, splints or damaged fibers with water.
-in most cases where you have a hole you should use FOAM (or the core material) not resin.
-400 grit is nothing there and in most cases; you cannot rid of the damaged fibers; cannot let a mechanical good surface for the next fiber; cannot flat right the surface.
—in this case: sand with 80 grit and the sander; slightly touching it; first the shatter parts then the area there. You stop when you see the cloth all around.
Pass styrene to check the work. In this case you will see the color of the board smooth with the rest.
Put the board on the rail; mask with tape put 2 layers of 4oz one bigger than the other. In the case that you need to level a bit; use more fiberglass, not more resin. Lam and wait two hours (or use UV cat resin) then hot coat resin. Sand the edges of the repair slightly with the machine then continue by hand with a EVA padded block (yes with a block)
80 grit, then 100 grit. Check that all is leveled with the rest of the rail; if not you need to repeat in the non leveled part until all is good. Normally in the first time all is good…
Clean the dust and apply a finish coat (you can utlize the hot coat resin) with a clean small brush. No tape the area; not too much resin. Fade out the edges.
After two hours start to polish (sand) With what grit depends on the finish of your board. If it s bright, after the polishing (320, 400, 600, 1200 grits) you need to rub out the surface.
If it s sanded use 280, 360 and 400. If it s “brushed” (matte finish but done on the gloss) use similar to the other grits then use a purple 3M sponge.
-My job is building boards.