I may be close to final sanding my build soon, so the question is - Up till what grit should one use hard blocks(wood) and when to switch to soft blocks(rubber) ? Say i'm sanding the flat region of the body with 80 grit paper attached to a flat wooden block, can I use this hard block up till 220 grit ? And then lay two coats of varnish, wet sand uneven areas with 400 grit with wood/rubber blocks. The reason why I am asking is, i feel sanding a finish with a fine grit paper attached to a hard block might produce witness lines, where as soft blocks wouldn't. At the same time a soft block could compromise the surface flatness under a gloss finish ? Also at what grit can one sand without a block and just use fingers without compromising surface flatness or quality ?