: My plan (critique as necessary) is: Sand with 150 to feather edges drips,
: sags etc, followed by 220.

If you have significant drips and sags, don't mess around, start with 60 or 80 grit. You can use a file, rasp or coarse sandpaper on a hard block to remove the worst offenders. Don't waste time with grit finer than 80 until you have really flattened out the surface.

: Cut hatches, drill/fill/drill all holes for deck fittings.
: End Pours.
: Install bulkheads.
: Sand all with 220 if scratches occurred, spots missed or slop from sealing
: hatch edges.
: Wet sand with 320.

Don't bother with 320 until after the first coat of varnish. Just rinse the boat after 220, wipe down with a clean rag, let dry, tack cloth.

: Varnish.
: Curse all the flaws I see and the bugs that seek immortality mistaking my
: varnish for amber.

Get the first scratch early so the bugs don't bother you as much.