VPI Classic platter - is center milled?

Wow. That seems like a poor decision on VPI's part. IME rubber mats suck. It makes no sense to raise the middle section so you have to use their rubber mat. Now if you want to use an aftermarket mat, it has to go on top of the rubber one. Or if you like the sound better directly on the aluminum platter, that is not even an option now.

Correct. With no mat, there is a 2 mm gap between the platter and vinyl so no vinyl touches the platter (excluding label).

I think it sounds very good (not sure what it would sound like directly on the platter); however, I do not find the ring clamp does much to even out slight to sever warps.

That's strange. When I had my Classic 1 with the previous aluminum platter, the VPI outer ring worked pretty well on warps. I'm not sure why the new platter with the rubber donut would be different. How tall is the donut? Maybe it needs a little more height so the label recesses more? How heavy is the ring clamp? Are you using the center clamp or weight as well? The VPI ring clamp I had was a good 4 pounds and flattened most records pretty well.

Sorry, I meant center clamp. I am thinking about grabbing the outer ring clamp, I agree, I think that will resolve the warped disc.

Does that mean that the clamp has changed as well?

For years VPI touted the benefits of the 1/4-20 thread on the spindle to mate with the clamping hold down system that they developed.