I felt like that was a bit rude, but, like you said, "this is just text". Text has a tendency to seem rude even if that wasn't the intention.

Regardless, I think I have an good idea what I need to do to keep my chain in place.

My final question concerns bottom bracket spindle lengths. Any Cross Check or other owners install a third chainring (I would install some sort of guard) on the inside? Did you need a new bottom bracket to give enough clearance from the chainstay?