If the idea is to sell blocks to sponsors then you might want to consider very large blocks with central areas available for the sponsors to place their logos or names. The center blocks could be paper or material ... pinned from the back, velcro'd, fused, or whatever you decide.
I would think the idea would be for the audience to be able to see the sponsors names would be the most important.
You could alternate or arrange your blocks with sponsor blocks if you want.
Just make it fun for you.