New Egger with a couple of questions

Hi Everyone.  This is going to sound like a familiar story here on the forum, but here goes anyway.  I’ve been lurking here for a couple of years now and feeling the itch to get my own Big Green Egg but the practical side of me has always held me off saying that I’ve already got a grill and can I really justify stroking a check for that amount of money to get one.  You know the story. 

Imagine my surprise when I came home from work last Thursday to find my wife and kids in the kitchen with big grins on their faces and a brand new Large Big Green Egg with a big bow sitting on the deck!  What a great early Father’s Day + Birthday present!  I guess my hint's haven't gone unheard.  Unfortunately I’ve been out of town and only had the chance to do some chicken so far, but I’m going to plank some salmon tonight.  Can’t wait!

Anyway, on to the questions….  First, a friend of mine gave me a 10 pound bag of pecans in the shells from his farm and as we have been shucking them I’ve been tossing the shells in the trash.  I know that pecan wood is a popular choice for smoking, but can the pecan shells be used too?  If so, I’ll be sure to keep them.  Secondly, is it easier to fine tune the temperature by adjusting the bottom vent and keeping the daisy wheel the same or should I adjust the top damper and keep the bottom slide constant or use a combination of the two?

Thanks for the help!  I hope that I can pass on some sage advice to the new guys at some point down the road.