Bow Tie Calculating

In July of 2013, I began my Bow Tie leaders & enders project ala Bonnie Hunter - Quiltville.  I last wrote about it January 2016, you can catch up (as I did) with this post.   I still have at most a couple dozen sets to sew into blocks.  I have 156 unique fabric blocks.  I have, if I counted correctly, an additional 203 blocks.  Of those repeat blocks, quantities are mostly 1 to 5 of each, but one of them has 18 more just like it!  

Black Tie Party, Project #043

I've calculated that the 156 uniques can be laid out, in the above pattern, at 13 rows by 12 columns, which finished will give a 39" x 36" unit.  I'm thinking I will add a 3" black border all around it.  That would bring it to 45" x 42".  Still just a bit small in my thinking, so perhaps another round of bow tie units (I obviously have no shortage of blocks), which then would bring it up to 51" x 48".  I could leave it at that, or add yet another two rows all around, maybe alternating the direction of the blocks.  I would have to cut and construct 3 additional blocks though...again, all depending on if my initial count, and calculations are accurate.  I'm not known for counting accurately!