How much worse would I play if I played blindfolded? Suppose I played a chess game with 60 minutes on both side. I play blindfolded while my opponent does not. Assuming that my rating is 2000 fide, what rating would my opponent have to be so that the expected score is a draw? Is this dependent on a person's rating? This question might be hard to answer. I am interested to know if anyone has any insight from their experience playing blindfolded.
I think it is ridiculous to assume that someone's normal rating would in any way be indicative of their blindfold rating. Your understanding of chess and ability to play with the chess pieces in front of you has little to do with your ability to hold all of the information in your head. 

The only assumptions you can make are:

A) a person isn't going to be better at blindfold chess than they are at regular chess

B) someone with a higher rating in regular chess is more likely to be better at blindfold chess than a lower rated player.