Thanks for the info. I choose to use sandable (and they say stainable) filler. After staining, the filler does look darker than the real wood. At least they are evenly spaced and perfectly round. The Golden Pecan stain produced a beautiful look. One would not guess that its a pine 2x12 stud after the sanding and staining.
Now, I have to wait for a warm day so I can use the poly spar varnish, and leave the door open all afternoon.