So we're look for 6mm and above in principle to be well protected, thanks all for your input. Every single post is both helpful and thought provoking.

Titanium is quite expensive, but never worked with it either so not sure if its for me i doubt i could weld it.

Its a good valid point that the lack of snag points / holes in the design limits the ability to further fling the bot and inflict immediate damage with the energy.

That said more holes also means lighter, but more snagging potential. Not something i'd considered.

Ripping off entire panels is some serious power brings up a good question too weld or too bolt together.

The next problem for me to think on is reach.. watching both battle bots and RW, it does appear that the more reach you have the less protection you need as the other bot just doesn't get close IF you can manoeuver well.

Or to go short reach does that actually mean less power over all less chance of the spinner damaging itself.