Those platers were specifically designed to use w/o a mat but to couple the record appropriately to the plater you have to use a clamp and a ring
(for another $1000). The ring is a PIA. SOTA, SME, Kuzma and Walker have much more elegant solutions to that problem. There is no such thing as a flat record although properly pressed 200 gm records come close. With any pivoted arm you are going to get warp wow unless you flatten out the warp. That is something you can actually hear. And, an appropriate mat should sound like absolutely nothing. All good mats should sound exactly the same unless you have a problem with your platter ringing. Tap to find out!