Before finish is applied, you can wet and let dry then, sand, several times. This causes the loose grain to fur up. With 220 to 300 grit paper, knock the fuzzy grain down and re-wet to do it again. Don't sand when wet. The end result is a very smooth surface that won't fur when that first coat of finish is applied. I like the thinning of the finish for the first coat idea. Then sand to nearly bare grain again. This gives you tight filed pores upon which to build your coats. I also don't sand any finer than 300 grit until the second to last coat, that coat is 400 and up. The final coat doesn't get sanded unless the type of finish calls for it. Usually, there's no buffing as smooth as that last coat. A quality brush is absolutely necessary or the streaking may nor settle out. Oil finishes are best finished with a cloth. Seal the grain and sand between coats of oil.
I've been a cabinet maker most of my life and recently started making art enhanced wooden parts like doors and hatches. Check out my new wood burned hatch boards I made for my boat Dragonfly. It's my profile icon. My new art.
I don't know anything about Cetol but the water-based spar varnish I used is fantastic. It is called UltraGold. Been on my kitchen counter for about 10 years, nothing gets through it. Never added more coats, 5 on the countertop, 8 on my hatches. The makers claim it out performs oil-based vanished for UV protection. It sure is easy to clean up and doesn't smell.
I like the cheap brushes from Lowes because I just throw them away instead of cleaning them but, even if they don't leave bristles in my work, they don't lady down the finish as smoothly. Its a very noticeable difference.
- Will (Dragonfly)