One thing to keep in mind, boards over 14' long carry a significant jump in per foot pricing making a 15' board much more expensive than a 14'...when I bought about 5 years ago a 14' 1x6 was $53 and a 15' was $70! It's worth your while to look over your design to minimize the impact of this. My upper deck is almost 20' wide so I picture framed it and ran a dividing board down the middle so I could use mostly 9' board on the field. that alone probably saved me several thousand dollars and it actually looks better.