Cheers, did the gantry slide on dovetails?

That was the same design as I had in mind, but then I bought some THK HSR 35 rails and thought it would be a good idea to make it move as well.

Probably looking at a square braced frame for the moving gantry and let the Y axis beam move up and down within it, I am also worried about keeping it aligned.

Although this is primarily to make guitars, Im in to Rc cars and offroad buggies, so scope for larger work would be good.