I finished my UDS this past week, pron to come later, and added provisions to the drum to use my Guru. I had the fan adaptor for a WSM or Weber kettle, so I simply put another 1 inch hole in the drum toward the bottom at the same level of the other intake ports and used that adaptor.
I started my seasoning run with the ball valve wide open, when held solid at 313 degrees for about 2 hours. I then closed it half way, which dropped the temps to about 230 for another hour. After that, I wanted to see how well the Guru worked on the drum, so I closed the valve, attached the fan and set the pit temp to 250 on the Guru. Once it stabilized, I saw that it would vary a few degrees up and down, I am guessing that it was sucking air through the blower even while it wasnt running, so I shut the gate on the fan to about 30 percent open, and it stuck at 250 solid...wouldnt budge. Changed the temps to 275...same thing, rock solid....300, same thing, solid...did this all the way to 375, which I think may be higher than I will need in the future, but it is good to know the drum will do it. The fan was running full time at 375, which could have possibly been lessened had I reopened the gate a bit, but again....375 is on the warmer side of what I will probably need.
The biggest thing I got out of my Guru trials, was a strong sense of confidence that the drum will do just fine on an overnight cook without worrying about any spikes or drops. The drum truly performs like an oven now with the Guru attached, and I am so glad that I made the investment.
Thanks again to all of the brethren who contribute on a daily basis, and have led me by the hand on how to build a UDS. I am a beginner at BBQ, but I feel confident that I now have the right tools to grow with and improve upon my results.
p.s. The first cooking run was baby backs...and everyone who ate them were moaning. The UDS is here to stay, with PRON in abundance once I get a camera!