Ana, I really loved this design and was pretty easy to build! I like the way the finish turned out by painting it black and just a few coats of poly on top.
The benches are overbuilt with intention of converting 2 benches into 4 chairs in the future. I made them larger so I can simply just cut them in half and add two 4x4s 18 inches higher than the current bench legs at 24" and just deck it as a chair back, seems simple enough. One thing I would change in the design is eliminating the 3 1x12s and 2 of the 1x4s and just going with a solid table top at 33 3/4 x 40 3/4, similar to what I did on the benches.
Let me know what you think and if you have any questions.