Its indeed difficult to rate a players game from 90 years ago, because we have not many valid video documents. It would of course be better to trust your own eyes and examine really sharp video material. However, the contemporary writing on Tilden by people like Laney, Danzig, Wind, Maskell or Myers is outstanding, because it describes the style, the techniques and tactics of the players and the courses and the turnabouts of the matches in a very detailled way. The reader gets indeed a perfect picture of players and matches, almost as if he would be himself at courtside. Sadly this brilliant tennis writing, which covers the bread and butter of strokes and games, is gone forever. By the way: The 20s is an era, which is quite well covered in written accounts and biographies or video samplers (for instance the Wimbledon video series), better than say the pro tour in the 50s and 60s. By studying all video and written material i could get , Tilden's game is to me more familiar than say the game of peak Hoad or Gonzalez, because we have even less video and written material from the pro tour in the 50s.