I've got some dents in my eccentric. Sheldon Brown makes a reference to them with this type of eccentric. As long as I can adjust the timing chain adequately, should I not be concerned?

Also, the captain's bottom bracket (or whatever it's called) has a very slight hitch in it (I have to hunt for it when turning with my fingers). The stoker's bottom bracket isn't quite grinding, but is noticeably not smooth when I turn it with my fingers (with the cranks off). Should I go ahead and replace both?

Tandeming is not a sport for the light of wallet.