Brisket is expensive! The trimmed flats are $4 / lb & the whole untrimmed are $2/lb ( lot of weight lost with trimming)
That's why I cook 20 butts for every brisket.
What I have been doing like you is cooking chuck roast,on sale here for bout $2.50/lb.
We are empty nesters & a 3 1/2 lb chuck is a better size. I like sliced brisket/chuck , I'll smoke till temp bout 160-170 then foil & pull @ 190 , I'll then put in fridge till cool , to let it "set" . This makes it easier to slice.
A chuck is perfect for your mini smoker .