In starting out the Kiss (keep it simple solutions) method of beekeeping is best. I would make all the boxes the same size--medium (16 1/4W X19 7/8L X 6 5/8D). Inner tops, telescopic top, slatted racks (to use instead of queen excluders), and screened bottom boards. Other than your usual protective equipment and tools that's really all you need.
You could go for the 8 frame width over the 10 frames which takes a 13 3/4 width. It's lighter and easier to handle--a definite advantage as you get older and, in my case, more decrepit.