I stumbled across this spreadsheet for calculating the spacing and lengths of elements for yagi antennas. You put in the frequency, boom length, and a few other parameters and it gives you the exact measurements you need. It also will take into consideration if your design is through a metal boom or insulated from the boom. It leaves the matching system up to you.
Here's another link to a program that also gives you even more precise calculations, including dimensions for using a folded dipole design for the driven element
Yagi Calculator
Here's another link to a program that also gives you even more precise calculations, including dimensions for using a folded dipole design for the driven element
Yagi Calculator