Uneven stock

Is anyone surface planning stock on the cnc that has small warps or bends but is too big for your planner? I’m thinking of trying this with a 20”x20” piece for a clock but it has some warp to it. I was going to place it cup side up and place shims under it so its solid and make several passes until that is flat then turn it over and surface the other side. I have a Whiteside 3/4 “ spoil board bit I was going to use. Thoughts or comments?

Using a router with rails to flatten stock is a well known application and is basically what the CNC is but automated. The X-Carve isn’t even that much more expensive than the Woodpeckers tool made for this: https://www.woodpeck.com/woodpeckers-slab-flattening-mill.html

I see they are doing cup side down. I think that would be better and safer but my material is only 3/4" thick so I was worried about it getting pressed to the spoilboard when the router passes over that’s why I was thinking cup side up and supporting the cup with wedges. Now thinking I could do cup side down and support the board with something under the cup.