971 Pan- windage tray needed?

Baffles help keep the pickup covered; the tray helps keep oil from getting whipped up by the crank and aerated. If you have one I'd use it. What I do that's worked very well with a stock tray, is get a pair of 'Superformance' brand gaskets. Install with a little sealer according to his instructions (which is the fairly standard technique of running a small bead on each side, snugging, then come back later and do the final tightening). Oh make sure all the surfaces are CLEAN first!