I agree with the triangulation. I added lots of additional smaller ones where I thought they would add strength.
This is some detail to show how the rollcage went in. I added some plate under the tub to tie the uprights into the frame. At the side of the dash, you can see one of the triangular gussets that are added for strength. You can also notice that I took some artictic license by movingthe front top back to allow the visors to go up and down.
It was only tested once and took the hit quite well.
And the moral of this picture is - Never let your dog drive the trail...
Even the Poison Spider cage (at least the one that I procured) only covers the front. I still need to add a strut at the back between the uprights at the top of the back window to ensure a good cage.