Lump...How Do You Separate Good & Bad...

pour the whole bag onto a tarp, and separate manually

Big bags are a crapshoot. If you'd ever used Ozark Oak in 10# bags you'd understand

I've stopped using lump charcoal and have started buying the all wood briquettes. Royal Oak sells them and you don't have to worry about uneven pieces. I've got a Stumps so bridging in the chute is something I have to be concerned with. The briquettes pretty eliminates that problem.

dump, shake, sort by size and into 5 ga. buckets

I used a UDS fire basket to sort a 30# bag of Cowboy. Seemed like a good deal until I opened the bag. If UPS had handled it 5 times, it could not be more broken up than what I got from Lowes. Damn what a mess.

I'm with BBQ Bama- I'll just stick to briquettes- all wood or otherwise.

I prefer Wicked Good Lump

I have used most brands but you have to manually seperate for smoking . I have had good and bad on all I have purchased .
Surprisingly the Westrn lump from Wally World that I bought on sale (thanks to the brethren for posting ) is the best I have used .
Still had plenty of fines but better than other brands ( R.O. B&B , BGE, etc )
Think it all has to do with handling and shipping to be honest .

Lay the bag on the ground and split the bag open, sort into buckets then carefully wrap up the bag, dust, fines and small pieces and toss in the garbage, keeps the dust cloud down this way.

It ain't over yet, but I've had pretty good luck with Made in USA RO this season.

one layer of briquettes and everything sits on top. dust pieces and all

It wouldn't truly be a lump thread if someone didn't mention Rockwood. It's the favorite over at the BGE (eggheadforum) site. Rockwood lump is consitently carbonized. Sometimes you can find deals at Ace hardware store. (look online if your local Ace doesn't carry it)

Compared to everyone else, I'm feel like my method is lazy. I just pour from the bag into my chimney starter, then take the really big stuff (if there is any), break it and toss it back in, and any little stuff that fell through the bottom I put on top. Usually works. I like Cowboy because it's been the most consistent to start.

My local BBQ store for a while had a rating system for lump/charcoal where they listed things like ash, burn temp, and other items along with a rating. At the top of their list the BGE charcoal was pretty consistently their #1 rated lump. And of course it was almost always their most expensive too. I believe that BGE branded lump is really Royal Oak lump in a green bag. After looking over at the BGE forums, I may have to try some of the Rockwood stuff. Never have but since a lot of BGE owners like it, I may give it a whirl.
To the OP's original question, in my BGE (which I use primarily as a grill verses a smoker) I don't sort it at all. I just take what pours out of the bag and set it on fire. I like mine 500 to 600 degrees for grilling and the random mix of bigs, smalls and fluff doesn't really come in to play.
I may be in the minority with this technique.