My first smoker was an old SM008, loved it. BUT I wanted bigger shelf spaces so eventually found a used SM150 thats just right.
Look at the specs for the SM009, I'm supplying the link for ya, it's right from this site,
http://www.cookshack.com/store...iginal-Model-SM009-2it states capacity of 20-25 pounds. At 19 you are right on the edge of the capacity. AND you need to fit it all on one of the smokers three shelves. I got a 15 pounder when I was still wet behind the ears and cut it in half near where the tip and the flat met. Put the flat on the top shelf with some bacon draped over it (tacked in place with cloves) and the tip on the middle shelf with the fat side down. Didn't remove one bit of fat from it. Came out pretty good, I was still in my learning curve with the SM008.
That's lot of work for the SM008 so go not by time (as is preached here anyway) but my internal temperature of around 195 and when you stick a skewer in it it slides in and out like it was a stick of almost melted butter.
Good luck.