I've done it twice... First time wasn't very good--second was excellent...
First time I didn't brine, covered in mayo/cajun rub and cooked to 175 w/hickory... Flavor was good but the meat was tough and stringy...
Second time I brined overnight in salt/sugar/old bay/water, covered w/mayo and cajun rub and smoked w/hickory (1.5oz) til the internal hit 195... Took a loooooong time--don't have my notes but I'm thinking 12-13hrs... Meat was both flavorful and tender...Didn't get too dry which I was afraid of... Cooked at 225 or 250 (probably 250) on my 009...sorry but I lost my notes...
Good luck--at least turkey legs are cheap to experiment on...