Re: When to tumble?
First off, NEVER tumble loaded ammo. You are really asking for trouble doing this, the dangers are many:
1. Possible (unlikely) that a bullet could strike a primer and set it off
2. Static build up of bits of powder rubbing on each other - thus setting the powder off
3. Bits of powder breaking up into smaller pieces, thus changing the burn rate of the powder charge - potentially blowing up the gun
That said, I use the stainless tumbling media now, but WHEN I tumble hasn't changed since I used a vibratory unit.
After the range, I use a decap-only die to remove primer - no sizing. I don't ever want to run dirty/carbon'ed up brass into my dies.
Afer decapping, I tumble brass then dry. For NS only, I setup my cases into a loading block, and apply a slight amount of Lanolin/Alcohol lube to the case neck, then resize. For FLS, well - I lube the all of the cases up fully. After sizing, tumble again. Then load.
As for case prep - I prep clean cases, then I clean prepped cases. I've found the stainless media "peens" the case mouth a bit, and therefore I need to re-touch the chamfer on the case mouth with my VLD tool after tumbling.