I size, then trim to length and chamfer inside and outside of case mouths, and then tumble.
ive found that when I was using lee case lube in a tube, It wasnt too sticky and I could just throw it in the tumbler after sizing.. But now Im using the Cabelas spray type case lube, and it gets really sticky and I use alot. I spray lube directly in to my die before I even start, and then hose them down with case lube about 30 at a time and shake them up in a bowl. After sizing with the spray lube, I use a bowl and collander to wash them with dish soap and then rinse them, before moving on to trimming and case prep. I like to leave my brass in the tumbler for like 6hrs at a time, so it comes out looking factory new.