Dust collection volume is like clamps - you can't have too many. Go for as much cfm as you can afford. If you are going to run 4" PVC tubing don't plan on a cyclone inproving the suction later. Do use the large radius bends. Cyclones like large ducts - 6" and volume.
Oh, and by all means get the best filter you can, .5, 1, 3 or 5 microns in bags NOT 20 or 30 microns.
Oh, and by all means get the best filter you can, .5, 1, 3 or 5 microns in bags NOT 20 or 30 microns.