I'd recommend taking more anti gunner on your curios instead of the 4-5% toughness which are only giving you 5-6 toughness each as your base is around 100 with this build. Instead you could have 60% Gunner resistance and tank way more stray shots. You did mentioned the staff isn't optimized but you really want burning to not be a dump stat as that's its main damage source. Carapace perk on it is almost useless, go for infested if you're only using it for horde clear or maniac/flak/crit chance for mixed hordes. (Crits apply double burn stacks). As you get more comfortable with avoiding attacks I'd also recommend taking fewer toughness regen talents at the top and take more utility near the bottom like near the bottom right is a talent that lets you convert blocks into peril which is great at saving your bacon from attacks that would otherwise have enough damage to go through your block and your toughness.
