I usually let mine touch in the dehydrator and don't get any spots as long as they aren't sopping wet when I put them in. I usually take them out of the tumbler and rinse them off in a colander. Most of the water drains off and any residual stuff from tumbling is washed away.
I also recently changed how I have been tumbling, I used to use Dawn and stainless steel pins. I started using Armor All Wash and Wax and no tumbling media. They turn out just as good as dawn and pins, but I don't have to spend time separating brass and pins. Primer pockets wont quite be as clean though.
https://stainlesstumblingmedia.com/stainless-tumbling-media.html
https://www.amazon.com/Armor-All-Ultra-Shine-ounces/dp/B001GJ9K8C
Add brass. Add stainless steel pins. Fill with COLD water until all that stuff is covered with water. Add roughly ½ ounce of wash & wax. Add ½ teaspoon Lemi Shine. Do NOT go overboard with the Lemi Shine or your brass will actually come out of the wash dull rather than shiny! Tumble 2-3 hours depending on level of filth. Enjoy beautiful, shiny brass.
Do a batch without the Lemishine / citric acid and see how it turns out. It’s conventional wisdom to use it for some reason, but I think it contributes to oxidation long term.
Get you some Southern Shine media, use a few drops of Dawn, and some Armor All Ultra Shine and see how it turns out (and lasts).