No offence intended, but I think 8mm angled is a bit overboard. Maybe if you're intending on getting hit all over, but nobody uses 8mm everywhere. Terrorhurz' wedge was 6mm I believe, and that bounced hits away just fine until it got pried up by Aftershock from underneath, after having been on the flipper. I know Battlebots is a fundamentally different environment to Robot Wars, but you have bots there with much lighter armour, and I can't imagine stinger's front blade is that thick either. I think you can get around using thinner stuff if you play to your strengths. Carbide has 5mm Hardox around the edge to my knowledge, though it's fair to say they rarely get hit.