I agree that using a clamp can be very beneficial.
My Basis table and clamp are made for each other, and they work great. And I rarely, (twice, maybe, in 8 years), have had a record warped so much that it affected playback.
The only drawback to the Basis clamps is that they are so $%#^$% expensive. (I think they are running $300 now, (if bought separately from the table.) Ouch! (I know they are very well made, but still, $300?)
My two cents worth.