As far as the rubber washer around the spindle. When I had my VPI I only used it on records that were 120 gram warped records. I found that 180gram warped records could crack around the spindle area if used and made too tight. It puts a slight concave so the warps are gone and the record is tight to the outside rim of the platter and yes the record will be slightly out or level. I never had an issue tracking a record when the washer was used.
I also think the concept was that instead of a vacume system this was the next best thing to remove warps and only to be used if the record was warped.
I also think the concept was that instead of a vacume system this was the next best thing to remove warps and only to be used if the record was warped.