Can the P/S be set on manual so you can duplicate the ISO and camera settings to check out your lighting ratios? You might want to practice before your friends come over, maybe position some pillows or something in their place. Watch for reflections etc and try to keep the key light 1-2 feet above their eye level. Try putting the fill at camera level from your shooting position, about 2 stops less than the key light.

Good luck with the shoot.

Sorry Steve, it looks like I stepped on your toes and pretty much said what you did. This is an edit right after I posted the above and saw your answer.

Hope your turkey day went well.