Nice work on the cage. Very impressed.
I like the side intrusion bars with the vertical stays. Very nice.
Are you running strut tower stays?
Are you seam welding the body too?
Another one you may like to add, is a stay which starts opposite the side intrusion on the main hoop, then finishes at the engine mount.
I dont think anyone has done this but after seeing how the Porsche run their cage to provide rigidity at the rear of the car. It may be worth the effort as it should settle the rear od the car down.
You dont need to use the heavy 2.6mm tube to the towers or anywhere outside the safety cell so you can use a much lighter gauge(and weight) pipe to achieve the same results.
The guys who built a few of the Bathurst 12/24hr cars did make a point to tie all the metal on the front strut towers together then seam weld as it helped with the handing of the car to a large degree.
You can see what they meant in the pic but a little hard to see but you are sure to get the idea.
Hope the words are of some help and congrates on your work so far.