Are those about 2.5" high?
The reason I mentioned the center border size is because you need to keep it on the same grid if you want the FG's in both borders to be the same size.
So, you could do 2" - 1" - 2" (all sizes FINISHED). That would add a total 5" - 2 FG's. If you make it 6", then the 2.5" won't work evenly on the outside border.
Not that you asked, but if it were me, I'd paper piece them in chunks - that way you don't have to worry about coming up short or long when you go to attach it.
One sec for a new diagram:
Again, it's just for proportion - I don't know if you're doing it with all different fabrics, or just different sky or geese on the different borders. I see the cream, but is that just the inner?
FG are 2.5" x 5" FINISHED
Inner border - top/bottom 14 FG each, sides 16 FG each
Striped border - 2" - 1" - 2" FINISHED sizes
Outer border - top/bottom 22 FG each, sides 24 FG each
Total 152 Flying Geese.