Just a thought to consider for all those who have tried everything they can think of under the sun for tear stains. Wilson has horrible watery eyes 99% of the time. I also thought it was due to food, possibly eye lashes or even tear ducks. Funny thing was that I started noticing that when he waked during the morning his yes were pretty much dry and then would start watering pretty quick. When he got neutered last week his vet checked his eyes out. His watery eyes are not due to any of the above. Wilson has "prominent" eye folds on both sides that press up again the eyes to water. I never would have though of that. Wilson's a year old now as of January. Also, I just wipe him down with cotton balls twice a day, sometimes more if needed, and he's never been stinky on the face or red from sores of the constant wetness.....just wet and stained. I too use baby wipes, Witch Hazel and Mal-A-Ket wipes which all seem to help.
Emma, who is 10 weeks old, has just started with a bit of wetness on her left eye but only in the fold. I'm not fretting over it at all right now as I think that's normal to some degree.