I could've saved you tons of time/money if you would've asked!
Find out who supplies McDonald's with these and fill 'er up:
P.S. - This would've been a perfect project for Milt. Could've paid him in parts. Those piers need to be level and you need more support. Consult a span table for 2 x 10's at those lengths. http://www.mcvicker.com/resguide/page013b.htm