it depends on the size of the blocks...the border should be in proportion with the rest of the quilt so it looks balanced. you may want to add a 4 1/2" to a 9" so you will be adding 13" per side...if that is enough, or some other combination of multiple borders to make it look more balanced than one big plain border.

Your idea sounds fine to me. I like big borders.

I ended up making the last border 8". It looks great. Thank you everyone for all you suggestions. It is a good thing I decided to do 8" because I would have run out of fabric if i had cut 10 1/2 inch strips. I have never posted a picture but will try to when it is finished.

That sounds like a great compromise. And a practical one, since running out of fabric is NEVER good! Hope to see your quilt soon. Posting pix is a cinch on this site.