The woodbox in your cooker should hold enough hickory chunks to totally ruin a full load of packers with a creosote taste.
Like the experienced cooks above suggested,maybe call Cookshack and have them get you out a fast trial box of hickory,along with anything else you may need to supplement your cooks.
They will not be dried out,but dried enough.They will come with good sized chunks to add approriate amounts.This way you will know you have good wood.
Possibly your vendor is getting kiln dried wood from a furniture maker?If so,you will never get enough smoke.
I assume the cooker is broken in and has blackened walls,kinda like an old iron skillet?
If broken in,it often will provide enough smoke for chicken without even adding wood.
The 260/160 can almost smoke with dried branches picked up along pasture fields out in the country .
Reference "smokering".Is it something your customers require,as it has nothing to do with flavor?
As to charcoal,for some reason Kingsford regular seems to historically be the brand that is effective.You should be able to load about a half pound of good hickory chunks and a couple Kingsford briquettes at the start of the cook and maybe another 3-4 oz chunk of hickory about 2/3 way thru the cook and handle all your needs.
let us know .