"as soon as I had smoke the meat went on"
there is your problem. Let it go for awhile until you get a nice thin blue smoke.
then put the meat on
and be careful reloading the wood. Try and load your cooker so that you are not throwing more wood on at 45 minutes.
Ok Joe Offset, New Braunfels El Dorado, Weber OTS 22.5 & 18.5, (2) Master Forge Charcoal, Auber ATC, charcoal retort Weber drum rotisserie