I made a 17" tall pepper mill as a special order and used a normal length mill kit. Instead of making the top knob a couple of inches tall, I made it 8" tall, burying the adjustment knob inside it. The owner's wife just loves it. I made the OD about 3" even though the length to diameter ratio is off because a real person still has to grip it. That silly mill had 25 12-segment rows in it but I made all the rows the same rough diameter to make keeping track of 300 segments a little easier.I am planning on doing a very large peppermill, maybe 4 feet tall. It will be functional, but mostly just a show piece. Wondered if anyone had any insight into proportions as far as diameter to height? I am going to use a regular grind mechanism and mill my own rod.