re: Table saw sleds, How 5 cut do you need to be?

Wood runners like you have are a different animal pottz.  When you factor in wear and movement of the wood, two is probably the better solution.  If I were designing a sled to sell, or for someone else, I wouldn't use wood because of the variability with humidity and the fact that it wears pretty easily.  On the other hand, if I was making a sled for me and I didn't want to buy metal runners, I could find some wood that was stable enough for the task and do like you did.  And like I said, my long post was just about theory.  Practice is what really matters in the end and if you have 2 wood runners and sleds that stay accurate, there's no point in fixin' what ain't broke!