When is it appropriate to create a new table in the WordPress database?

Question

For a client we'll need 29,000 terms (all the highschool's in the US) and each term needs 6 meta items (address, phone...). My initial thought was to store the term meta information as suggested in this post but after looking through it again I will be using lots of terms and I wonder if it will overload the options table.

Is there a good time to create a new table? Would this qualify? Other thoughts on how to relate the HS that a person attends to the 'post' that will be their academic profile?

It was suggested that I make the 'terms' a Custom Post Type. I'm not opposed to that either but I fail to see how I'll relate the CPT to multiple 'authors' since a school will have more than one student that attends it. Because of the multiple ownership of the content terms just seemed to fit better.