Guys looking to machine 1.25x18x27inch plate as flat and parallel as possible in either 6061 or 7075 skimming off as little as necessary to get it right. I could possibly go up to a 1.5" thick plate. How flat is realistic? Would .001" flatness along the whole plate even be possible? Machine is a fairly low hours Haas. Thinking of using a vacuum chuck and dialing down the PSI as low as possible.