got a little further on the sore support restructuring.
i removed the top channel that was originally there and used a piece of 1 1/2"x1 1/2" 12 guage tubing. the stock stuff was pretty flimsy after my cut off wheel attack. i also figured i need to add back some of the stiffness vertically. the channel i added in in the bottom and the tube at the top were actually very stiff. unfortunately the 16ga. material the core support is made of flexed through its vertical run due to the fact that i cut all of the dimension out of it! so some 2"x2"x.120" tubing is being added to tie it all back together and generally re-rigidize (<-- new word) the thing.
no real good pics of the new upper tube but it cleans up the top of the core support quite a bit.