my guess is that you will be fine out under the REAL stars. PHD (after a flip) will "find" a suitable star to guide on , assuming you have that option checked in PHD and assuming your guide scope/camera can find one. I would strongly suggest that you track a few degrees PAST meridian before you let SGP do the Flip. Just make sure it is super safe to track past the meridian so as to avoid any mount crashes. You also have to have SGP do a centering routine because after a flip she will be quite a ways off from your original framing .
Dennis