The first lump I used was a gfs 20 lb bag which supposedly is royal oak. It seemed to burn well but there were a lot of small pieces. Well menads had the green bag royal oak on sale so I stocked up a little...(10 bags). Today I did an 8 hour butt cook and here's what I noticed: royal oak has HUGE pieces compared to gfs only minimal small pieces in comparison. It also seemed to burn a little slower and less ash. Has anyone else used both?