After reviewing many a magazine and multiple solutions for dust collection with this beasty, I decided to roll my own based off of BlankMan's / Degoose's designs. the designs both include plenum chambers to spread the suction across a small horizontal opening. Both solutions have the mainline for the DC above the bench, mine of course is below. With this all in mind and since I had pulled the benches off the shop wall, what I decided to do was to build a separate plenum box and integrate it in to the top of the bench itself, and then size the opening in the top to the dimensions needed for the current miter saw. I cut the center section out of the bench where the saw lives and left a 6” 2×4 support stubs on the back of each bench. I then built the plenum chambers length to make up the difference which was 29 3/8” in length. After having a chat with BlankMan I decided to make the interior of the chamber 6”. Since I am using ½” ply wood that meant exterior dimensions would be a bit under 7” (since this ply was .490 thick). I then ripped the sides and bottom. Centered the hole for the DC port.
I made a mistake here with a wandering jig saw and had to use a decent amount epoxy to fix. The fun part was since the port is at a 45 degree angle I went ahead and put a small drum sander on the end of the cordless drilled and shaped the outlet to the dust port exactly. I then attached and glued the sides on. 
Next up was the plenum divider board. I am still playing with the its final height but I think the hole placement will work long term. 12.5 sq. Inches was the goal in total “hole” space. After scratching my head for a bit, I grabbed the laptop and started inputting the diameter of my forestner bits to get the area of the circle. Once I got these figures, some division and addition later I came up with the hole sizes and counts. I end up with 2 – 2” Holes on each end, centered and 5” from the end. I then cut in 8 – 1” holes between them (used SketchUp to divide the holes up even across the space).
For testing I taped on some pieces of hard board to simulate the top with a centered ¼” slot.
I plan to play with the layout at bit more but at this time it works beautifully.