Use scraps to offset the straight edge allowing you to cut each edge of the dado with opposite edges of a router bit
Masking tape and a sharp knife are hard to beat for production precision
Make a pattern using elliptical sticks, and then use a router with flush-cut bit to replicate onto the big stock
Use tape to clamp and only glue where you have to.
First-time attempts at joints this woodworker has never seen before
All you need to build this table is biscuits, bowties, Festools, and straight edges...
Hey Samurai, Aren't you afraid of expansion and contraction? Samurai: "No, I am not afraid of expansion and contraction, and here's why..."
Nice boxes, no-shift
Composite decking machines smoothly, joins well, and resists weather with the best of 'em.