My leather care experience is similar to what you've described: Leather should be treated prior to getting wet. Based on what I've read here and elsewhere, apply saddle soap (Proofide) to underside of saddle and use fenders. After a wet ride, wipe dry and allow leather to dry, preferably inside (not in the sun or excessive heat). After leather dries, apply Proofide. If you condition the damp leather, you'll drive water into the leather.