I haven’t read every post in this one, but I DO trim pistol brass, and my process seems to be quick enough.
I prefer to sort by headstamp to better ensure consistent internal capacity. Then I size everything, and lock a set of calipers at minimum trim length, and start sliding cases into the jaws. Anything which doesn’t fit goes right, anything which slides through with clearance goes left. If in the end I have too many in the left bucket and not enough in the right, I consider shortening my standard, maybe scratch off 5-10 thou and rerun the left bucket into a fresh right bucket. If it adds a sufficient amount, then I set my trimmer to that length and add both right buckets. If there’s not enough additional brass to be worth my time in the “short spec” bucket, then I carry on with what I had from the first culling.
It’s quick enough I sometimes will pick a “halfway between max and min trim,” length as my starting point instead of minimum trim length, and work from there. I can pass cases across the calipers WAY faster than measuring every case individually, it’s just a specification spanner at that point.
Another method which is fast - but wastes more energy unless you have a powered trimmer: size and trim all of the brass to your desired spec and rack them. Any which didn’t get trimmed will be obvious by the tarnished mouth, rather than fresh cut brass. If your brass is too clean, rack them and roll an ink roller or press an ink pad onto the rack to give witness fluid to your mouths. I prefer the former above because I only trim what is in spec, which is the greater time vacuum in my set up.