I'd love to know exactly how you did this. How did you attach the dial indicator to the arrow saw? Any photos? For years I've heard of people complaining about this, but I've never had a way to check arrow straightness over a 28" distance or whatever the standard distance is. I see how the arrow saw conversion might work.

Like Arthur says, check spine with a tester for a real eye-opener. I've found that by spine tuning my arrows, that straightness didn't seem to be a factor in bad broadhead flight. If I could get spine matched arrows with the cock feather on the stiffest side, I got great flight. the only time flight was poor, was when the spine was too far off the average for the group. For this reason, I won't shoot an arrow that isn't spine tested. It's that important on carbons. I've never had a way to test straightness over the full length of the arrow, and because of the flight that I get off spine-tuned arrows, I'm not sure it's that important.