SM-160

Welcome to the Forum and the cookshack family! Don't worry about your first few cooks, they will get better with time. You will find a massive amount of great folks here who will pitch in with advice.

What temp did you cook them at? On the packers, did you have the fat-cap down or up? Most will say to keep it down so the rising heat does not dry the meat out. If I had to guess, I'd say you had the caps up and the heat dried out the bottom 1/3rd of your meat.

Packers have enough internal fat to keep them moist. At what internal temp did you pull them? I usually shoot for 190, any lower and they are still tough, much higher and they begin to break down too much, which is fine if you want pulled brisket sandwiches.

Also, did you foil them? I never foil briskets, but many do.

The 'rest' after cooking is one of the most tenderizing steps, IMHO. Pull the briskets at 190, double rap them in foil and wrap them in blankets, shoving them down in a preheated coleman cooler for a couple of hours. They will stay hot for a long time and the longer they rest the more tender they become.

I own a SM150, the black steel (outside) version of the SM160 - your unit has twice the capacity but is fairly like mine.
You should find a button on the lower right of the control panel that has a cows head and says BRISKETS on it. Apply your rub, put in your wood, place the brisket fat side down on the middle shelf, close her up, turn on, hit that BRISKETS button and START and walk away. DO NOT open the smoker for 11 hours, check the meat for tenderness and temperature with a quick read digital thermometer, it should be ALMOST perfect, around 190. Half an hour later it should reach about 195, it may take a little longer, as Smokin' says "it's done when it's done". 195, that's when I like to pull and foil my brisket for the long rest that Chaplin Bill describes.

It's that simple. I usually start my brisket about 9pm and when I get the wife off to work it's almost time to check the smoker. Can't get any easier...

Thx guys. What about removing the point from a packer so that the flat will cook more evenly? I will try 2 briskets next time. Bottom one fat down. Top one fat up. Should i lower temp if briskets are on mid and bottom racks? I'm a backyard cuer, transitioning from a Traeger where I had to smoke outside then oven finish inside.

Do just one thing at a time.
Try my suggestion:

one brisket, middle shelf, fat side down
good rub applied ALL OVER
225 for 12 hours
at Hour 11 check temp/doneness
It's done when it's done
Foil to rest at least an hour

Keep it simple
Take good notes of what you do each time.
The less complicated the better I think.