Consequently, I don't remember a thing I did at the time. A lot of water under the bridge both literally and figuratively. The previous job left a nearly perfectly smooth surface. Using a brush this time, I'm running into marks.
I surfed around until I came to a skateboard forum. The guy uses Polycrylic on all his boards. Up to 25 coats with sanding and buffing in between. He recommends cheap foam brushes.
Now I have a passel of those on hand. Another day or two.
The sanding and filling went fine. The cheap Black & Decker Random Orbit Sander is doing a fine job so far.