The old saying of "there is no free lunch" is true. Adding a baffle to the ring of the DC will reduce CFM a bit. So having the baffle in the ring, plus a separator, may reduce CFM more than you'd like at tools that generate more fine dust (bandsaw, sander, table saw even).
If you're going to do both, I'd probably configure the piping so only the jointer/planer/floor sweeps are in front of the separator, and everything else is direct to the DC.