Hi Aaron and welcome to the forum
That is an interesting Kettle BBQ you have there. Is the centre partition one you have created using foil or did it come with the BBQ? Just because it is "cheap" does not mean that it cannot do just as good a job as the more expensive Kettles...
There was also nothing wrong with the size of that piece of brisket. From the photos it looks like it has a good thickness of meat and, unless you are cooking foe a crowd, there is no point in cooking a whole one just for the sake of it. Having said that though they do freeze well.
What are the bottom and top vents of the kettle like? They are hard to see from the photos
How were you measuring the smoking chamber temperature? Does the kettle have a lid thermometer or were you using one at cooking grate level?
Was the meat actually dry or was it just firm to cut? From reading your text you seem to have had it in the smoker for about 5 1/2 hours before putting it in the cooler. When you say the "cooler" was this an insulated box that you were using to keep it warm - as opposed to the refrigerator? How long did it stand in the foil in the cooler before you cut it?
A long cooking time is key for brisket as it takes time for the tough fibres to render down. 5 1/2 hours is a little too quick for this to occur - especially if it did not then have several hours of resting in the foil afterwards.
With the amount of briquettes you have in your photo, burned using the minion or snake method, you should have been able to get a good 6/7 + hours cooking without refilling. What type of briquettes were they? Investing in good quality briquettes rather than supermarket brands is always worth the investment.
In your other post you were asking for advice on other smokers that we would recommend. What kind of things and how much do you see yourself smoking?
57cm Weber Classic or One Touch Kettles are good all rounders and if you are looking for larger quantities then a Weber Smoky Mountain (WSM) or a ProQ Frontier bullet smoker. I would avoid going for any of the low end offset smokers as they will be hard work and most are actually more style than substance.
Great post - Thanks - It certainly deserves a point