Thanks folks! I'm really happy with how it's turning out myself.
It's really hard to keep from starting the finishing process, because I so want to see it with a coat of oil. However I know that measuring and milling the armboard will require me to be moving it around on top of the table, and there's no use scratching up a finish until that's done.
The armboard will be thicker than I had thought, so I had to glue up two 3/4" pieces of Walnut. The armboard is going to need to be 29/32" thick by my calculations. I'll mill two screw slots in it for fine adjustments, and I'm not sure of the shape yet. I'm thinking one side will follow the contours of the platter, and the other three sides will be rectangular. I'll just wait until it's time to mill it before any final design decision.
I love it! That would be a dream job for me for certain.