[pikfish]

Hamer, Try using a longer stiffer fairing knife to get a straighter finish. I use dry wall mud knives from lowes they are cheap and work great (Get atleast two).If you work careful you will have very little sanding. Hold the knife vertical while dragging across the surface so the blade won't bend and the end result will be much straighter. Make sure that any roughness is removed before applying the fairing so as to end up with a straight, smooth finish.