A few months ago someone posted a formula for determining spine for wood arrows. I used it to get some shafts for a BW I use to own and it worked perfectly. I know you had to add a bit and there was about 4- 5 steps of math. If someone has it please post it. that was pretty helpful.
Foxfire archery has one on its site. Think the web address is Foxfire.com, but not sure. Can Google it.
Sent you a PM.
Steve
http://tradgang.com/cgi-bin/ultimatebb.cgi?ubb=get_topic;f=1;t=066430;p=1
Search "How I tune a bow from an oldtimer' by Danny Rowan. Might be the formula your thinking about.There's another one thats a little different but I can't find it.
Thanks Gray Wolf. Brought it back up. That was what I was looking for.