I think what people need to understand that it was nadal's forehand that made Fed's backhand better. So when he is able to handle his backhand with guys like Murray and Nole its because Nadal went after it time and time again and fed had to improve it. Get those guys out of the picture and Fed although has a great backhand is not as strong as it is today so those guys would be able to exploit it. The two things better today in feds game is the serve and the backhand. But he's lost his explosiveness, court coverage, recovery and the once legendary forehand (especially the one on the run). I honestly think if he had today's backhand back in 2006 or 2007 he wouldve beaten Rafa in those FO finals but as Fed's backhand kept getting better so did Rafa as a whole. But to answer OP's question Id say about 23-24
Intellectuals solve problems, Geniuses prevent them
RAFA2005RG- "If he (Rafa) lost Roland Garros it would be like death."