Hi there and welcome!
I'm with Smokin on this.
That seems to be a lot of trim, if you were making a pastrami out of it then it looks like a great trim to have very little pastrami fat.
Since you are making a smoked BBQ brisket, that is a lot of fat trimmed.
My trim job takes about 3-4 min and that is mostly just flipping the thing around. I don't even trim anything off the meat side, any fat or thin tissue there will render away or burn up or turn into bark so not worth the effort.
On the fat side I will trim down fat that is clearly over 1/2 thick. I stopped chasing 1/4 inch thickness because it's too easy to trim too much trying to get 1/4 inch. So I just trim to reduce the very thick amounts of fat and if it's over 1/2 an inch but close then it is good.
I too cut out the big thick deckle fat that doesn't like to render down BUT I then cut that into slices that I lay on top of my brisket around the edges of the meat, especially the edges of the flat. I cook my briskets fat side down because my heat source is coming from the down side. I then lay the excess trimmed fat on the top meat side of the brisket and boom, fat on both sides as much as it will cover but targeting the edges and the flat!
Finally, to me the most important trimming is actually cutting away good meat from the flat, and then repurposing that meat for grind, stew, braised dishes, etc.
View attachment 723367
In the picture I remove the green area because it is so much thinner than the rest of the flat muscle. I cut it away in a "U" shaped cut because corners on meat like to dry out but rounded edges not so much.
Notice the black circles indicate that what is left of the flat muscle is about the same uniform thickness throughout the flat and it is plenty thick for the flat. That is the goal.
The green part will almost always burn up or dry out on you, so why waste that meat when it can be used for something else amazing.
This part of the trimming is the MOST important to me. You could leave all the fat on if you like and still be ok but there is no way the dried out or burnt up end of a flat will ever be ok. So just repurpose it :D
I cook my briskets unwrapped the whole time in my electric MES40 which holds moisture like a champ without me having to add a water pan or anything.
The trimmed fat, and deckle slices are laid where the green line is and along the sides of the flat and then I just start to cover up any exposed meat starting with the flat. The main thing is extra love for the flat and the flats' edges helps it out and allows for great bark.
Also the beef fat renders and gets crispy and becomes... beef cracklins!!! Those things are out of this world good!
If you want a lot of details on this trimming here is the full post on it:
Well I have had a number of private messages where people ask for more info about what I do when I trim away the thin Flat portion of a brisket I smoke. So today I figured I would just post about it with plenty of pics so it becomes easier to understand vs when I just go "blah blah blah trim...
www.smokingmeatforums.com
With how much you trimmed your brisket I would pretty much guarantee you will need to wrap that thing at some point.
Don't fall for the hype of "wrap at 160" or "165" because that statement doesn't contain enough important detail.
***If you wrap too early you will end up with oven flavored roast beef instead of smoked bbq brisket flavor!!!!!!
Wrap when the color looks like a good smoked BBQ brisket (not roast beef) and the bark is there. That definitely will not be the case as it just hits 160-165F starting to stall.
Another detail the "wrap at 160-165F" statement leaves out is that the reason most people do it is to speed up the cook and speed through the stall.
You sacrifice massive amounts of flavor playing this game, screw that! lol.
I generally won't wrap anything before it hits 180F unless it is lean wild game meat. So hopefully knowing my 180F min wrap info AND the tried and true "wrap when it has color and bark", you will be able to cook your brisket success.
A brisket is only done when it is tender, never by time or temp. It is tender when you can stab all over with something like a wooden kabob skewer and it goes in like butter ALL OVER.
You only let a thermometer tell you WHEN to CHECK for tenderness.
So recap. That brisket will very likely need to be wrapped. Wrapped when it looks good or like it needs it (probably foil with that brisket and throw in a couple of shots (2-3oz) of water when wrapping it) and cook it until it is tender!
If you have more questions let us know because there is a lot to line up when cooking a brisket. I covered some important things but we didn't even talk about how to plan/time the thing. Let's absorb this info first and then move on to timing if there is an appetite for it :D