Hello, I am finishing the attic with Gable sloped ceiling. Collar beams will be exposed but high in the ceiling. I have 16' track lights to fill. Ridge beam is at 91" from floor. Area is 12' wide (by 91" long).

I was thinking about Trac-lite by Juno: http://www.junolightinggroup.com/system-details.aspx?id=162 and flared gimbal PAR30 heads (I will change the bulbs to LED): http://www.junolightinggroup.com/product-family.aspx?name=JU-R532&xtmc=R532WH&xtcr=4

Any idea about how many heads I need?

Thanks in advance