Fall-off the bone is easy...3-4 hours @ 225*, then foil for another 1.5-2 hours for the loin backs...if you want to firm-up or set bark, just reducer the foiled time by approx the time you want to return to open grates, but 30-45 minutes open grate will set the bark to medium texture...longer if you want really well-set bark. 2-2-1 is a typical baseline for loin backs/baby backs. 2hrs open-grate with smoke, 2hrs foiled, 1hr open-grate...this gives a semi-tender rib with a pretty decent bark.
CSRs will depend on thickness of the slices, but they won't take as long as loin backs. Figure on 2-1-0.5 for a very tender CSR with a modrate bark...omit the open grate final stage of cooking if you don't want bark, but lengthen the foiled time to allow for a nearly fall apart texture...same for the loin backs.
BTW, welcome to the SMF family!!! Enjoy the forums and all the great people who contribute.
Eric