We ran straight #25 in a pretty bad way; direct center-to-center with sprockets outside the tube. That being said, we only threw a single chain the entire year, at SVR, due to the looseness getting extreme because of some screw holes widening (haven't checked it out for sure yet though). We did not break any chains. We used the Dark Soul chain tool to rejoin it, which I think helped a lot; we've killed masterlinks in the past.
That being said, if I had to do it again I would use sliding bearing blocks for tensioning and run 25H or 35 chain, just from fear. I was in a constant state of fear.
