Great Idea Captain!
I have an apparatus like that in a slightly different setup for working on slot machines of the mechanical type at my customers homes as space to work is usually limited on in home service calls!
I lay a small pad down in the area I will be working and set the turn table assembly down on that for easy access to the slot machine at all angles!
I like the design of this also as both the upper board and lower board can be permanently fastened to the turn table by making a small hole in one so as to line up with the hole circled on the "Lazy Susan" hardware!
Great Idea, you must be a cabinet maker? LOL