I cook all my briskets at 300 they go four hrs unwrapped then I wrap in a single layer of Butcher paper they go probe tender in the thickest part of the flat in 2 hrs or less unlike some things size don't seem to matter much. Congratulations to your daughter! I wouldn't fret her growing up in a few years there will be Gradbabies then the fun really begins Trust me!
I never met a Cow that I didn't like with a little Salt & Pepper! Certified PORK-A-HOLIC