[LLogan]

Well, first off, the middle wheel will spin in a different direction than the two outer wheels because of the way your chain is right now. I also don't think that chain-run would work (even if you neglected the fact that the middle wheel is spinning in the opposite direction) without any sort of tensioning system. Even then it would have a higher chance of slippage because there isn't adequate chain-wrap.

In my team's past experience, we have always found it difficult to precisely drill holes into 80/20. When trying to offset the holes by 1/8th of an inch (which I am assuming your middle wheel is) the drillbit tended gravitate towards the channels of the 80/20 because it's unlike drilling into a uniformly smooth surface. However, we centered everything manually and used a drill-press.