How many of you Brine your chicken/s before you smoke it? If you do...other than adding Kosher salt to the gallon of water, do you add spices in with it?

You can brine and I have. I would definitely spatchcock it though. Makes it cook much more even. YouTube how to do it.

Yes, I brine. Depends on what I'm doing with it how it's spiced. Achiote, garlic, ancho, onion.... or rosemary and thyme. Or crab boil and lemon and garlic and Cajun seasoning.

Use your imagination. It's chicken.

I put two spatchcocked birds in a pale brining now for 4 hours. Should this be long enough?

I don't brine anything and my birds turn out moist and tasty.

I never have brined either but I thought I would try it. In few hours I will be putting it on my modified Ole'Smokey 22", using my competition blend wood pellets at 250* for 4 hours.
The rub I will be using is this:

1. 2 tbs paprika
2. 2 " chili powder
3. 1 " thyme
4. 1 " garlic powder
5. 1 " onion powder
6. 2 " cayenne pepper
7. 1 " salt
8. 2 " blk. pepper
9. olive oil to coat
I used 1 tbsp of cayenne instead of two

I do, and it works. I haven't added seasonings as I figure the smoke flavor is plenty good enough. Pecan smoke.

I rarely ever brine

Yep, I brine and inject. use 3/4 salt to half gallon of water and 3/4 cup of this stuff, http://bigcountrybarbecue.com/?page_id=112

After 4 hours, I put some of my SIL's fathers homemade BBQ sauce on them birds and in a few minutes I took the birds inside. They came out great and mother loved it. Not too much of a Bite with 1 tbsp of cayenne. I may add just a touch more next time. Excellent smokey flavor. Sorry..no picks BTW: the 12" TUBE I put pellets in burns for a full 4 hours. I haven't tried the "Wedgie" yet.

I don't because about 10% of the package is water. I just season it when cooking, and they never come out dry. I would probably reconsider this if it was a free range chicken.