Well, I am never happy with anything first off...
My 4 by 6 foot 1" thick MDF top has developed a small, but annoying curl upwards (about 1/16" off the rollers).
I have another plan... I will get a sheet of 10' long by 5' wide MDF by 3/4" thick. I will cut it in half and glue it up in thickness.
I am going to rig up some sort of ball bearing roller, that will be fastened to the inside of the Buddy aluminum channels, and push down on the top so the top is basically captured beyween the bed rollers, and the rollers I will install. I think a piece of milled steel angle along the edge will be better than running right on the MDF.
Then, after leveling off the top surface it should stay very flat.
Once my Buddy is in its permanent location (within a few weeks, I am getting some renovations to my shop to add another 185 sq feet just for it) I will get to work on the new table. For now and for what I am working on the existing table is OK.
More later when I get going on it...