Jim, to be honest I don't remember how much it weighed. Being that I cook by thermometer, I very seldom pay much attention to weight.
I want to say it took about 4 hours or so, but don't hold me to that. I did try to maintain my temperature at or around 300 and I think I picked up the lid one or two times for a quick peak. I never did turn the breast, but kept it back side down.
Wished I could be more on the money for you where as time and weight are concerned. I would suggest that you do cook by thermometer, when you hit 170, pull it off the pit, wrap it in foil and put in a cooler for a while. I do that with just about anything except bbq chicken pieces. Those get pulled and eaten right away around here.