It will cook a little faster parted out than whole. Best of all, you'll be able to remove the breast meat as it gets done and not have to leave the white meat to get over done waiting on the dark meat to get done.
I hate over cooking delicious white meat waiting for the gross dark meat to get done :x
Not a dark meat fan, I usually cook breast instead of whole birds. For Thanksgiving and Christmas when we have guests that enjoy the dark meat I cook a couple breasts along with 4 drumsticks and everyone is happy!!
It's about like any other large mass meat (butt, brisket, turkey) 1.5 hours per pound is a good time to allow for. I'm personally not a big fan of smoking by time. I do better with temp. Just follow the guidelines for poultry doneness (I think it's 180?) and keep your cookin temps around 225. Be sure you get your temp reading from between the thigh and breast. The breast will hit its temp faster than the thigh area will. I haven't had a problem with dry breast meat but I have seen a lot of others that did. They suggested foiling around the breast when it hit its temp to try and hold the moisture in. I would think you could inject some butter and seasonings to add more moisture and that might help.
Maybe I just like my white meat dry so I don't notice it. :D
I'm sorry I have not been up to date on your posts, but smoked turkey is the best. Here are a couple of pics of our T-Day cook last year, and I hope Cajun has you straightened out with the pics.