You may not have a lot of options.
Yes,if you can see fat running thru the flat,rather than all on the exterior that would be nice.
I see you have a smokette,which was built by Donna's family a half century ago-as a brisket cooker.
It does great.
11-12 lbs is about the limit for size,so you can pay attention to shape,as well.
I see you now have a new FEC.
You can always trim a few bites,to help fit and bend the packer up a little.
It can touch walls,as it will shrink,as it cooks.
We all start out wanting to do the perfect one,to start out.
The search for the great one can be frustrating and too,too time consuming, for what you gain.
Personally,I think more is gained by cooking a few,of what you can get, and gain the experience.
The nice thing about a CS is that our lousy ones,will be better than most other folks fine ones and they will be pretty good eatin'.
In a perfect world,a thick,even flat would be nice.
A limber,bendable one is nice.
The folks that have tried to teach me,over the years,like about 15-16 lb packers.
The size, lets you have more,different samples and approaches.
You are talking about 50% loss,and any leftovers freeze well.
Most of our conversations tend to rush into the perceived perfection of comp briskets.
I think ,if you just cook some,you will get some slicable meat,a few slices that are really pretty to serve.
Some short,long,thick,uneven looking.
Some inch chunks,some flat and some point that will chop to plate,or make some sandwiches.
Some little odd bites for the cook and friends.
Cooking a dozen ,not great, packers,over this year and taking good notes,will give you a lot more conidence,and skill,than hunting for and cooking a couple great ones.
...and a lot more fine dining and fun.
Jusy my $0.02,and you know what that's worth.