A few alterations I made to your original design plans:
1. I went with 1/2” plywood and bead board for the back. This gave it a little more stability and a complimentary design element to match other pieces I’ve built.
2. I used 2x3’s instead of 2x2’s since the selection was much better at the lumber store.
3. For the bench top I used a black walnut slab cut to size finished with a danish oil and satin poly top coat.
4. Instead of the X, I enclosed the sides and used a pair of parallel 2x3’s backed with poplar boards cut to size.
Thanks! I hope you enjoy.
General Finishes satin top coat
General Finishes Antique White milk paint