DJ,
I don't think you'll have a tough time move techniques from one smoker to a different smoker. The pan to catch drippings shouldn't impact the time (unless it served as a heat sink and absorbed all the heat in the smoker).
How big was the brisket? You only smoked it 9 hours before pulling out of the smoker?
What was the temp of the brisket when you pulled it out? Your smoker will work fine, you should NEVER have to finish in the oven.
As for tough as shoe leather, I'd wager you didn't cook it long enough as opposed to it being dried out/overcooked. I don't care what temp it says, I still use my senses to determine tenderness, not temp alone. When I insert the probe inside the brisket I try to get a feel for how easy it goes in?
RS is right
It's done when it's done A lot of people poke fun at my famous saying, but think about it. The brisket will tell you when it's finished, this isn't like baking a cake with a specific time and specific temp to finish a specific way.
You might also want to check your smoker, when you had it set at 225, was it 225 internal?
And you'll need to change the title of your post, Brisket 101 is a registered mark of mine
Have you seen Brisket 101? click on the guide page in the navigation links at the top of the page and look for Brisket 101