I love, LOVE my built-in miter saw stand! No more using my saw on the cold cement floor.
I took others' advice and used pocket hole joinery to connect the bases. It was a lot more solid with this modification. I also secured the top and bottom of each cart with additional screws around the perimeter to prevent separation. I used MDF instead of plywood because plywood is crazy expensive right now! In retrospect, it would have been better to splurge on plywood since MDF splits easily and is more sensitive to temperature changes.
I painted the front of the carts Chantilly Lace by Benjamin Moore and attached the hardware using an old cabinet jig leftover from a previous project.