@Clipsey. Solid looking build so far and quite a change from your last screenshot so well done
I agree though, coming from high toughness to a more balanced figure is quite a shock but I reckon that is playstyle more than anything. You should see the state of me when I go back to my DPS build from my 700k build lol I feel squishy where as in reality, I am just not taking cover as much. (translated to - running around like a pleb lol!)
But, I will give advice on what I would do to that build but bear in mind differing playstyles etc:
Firecrest vest I would get rid of simple because it has no talent on its own unfortunately, and I would replace it with either a vig chest or reckless chest. (both readily drop in DN)
For PVE, either is fine, for PVP, vig would be better.
In terms of gearset pieces, I can see the mask is rolled towards electronics and based on the electronics value it doesn't look like backpack or mask have SP rolled as the major attribute so I would try and get those two pieces with SP rolled onto it already.
This will allow you to roll that mask towards firearms which would give you circa 3500 firearms and unlock all your talents on weapons.
For gear mods, 4xstam + sp, and 1xfirearms + sp would give overall (roughly)
3500-3700 firearms value
Around 390-420k toughness
Around 28-32k SP
With a booster shot on the side but those values could easily be changed by adding in stam _ health mods for more toughness, or firearms + crit chance for more firearms etc
Alternatively, if you get a sentry chest, go savage gloves for the crit hit chance boost.
The above values are based on SP mask and pack though.
If you chose to roll the mask now to firearms, the firearms value and toughness would stay the same as I posted, but electronics would drop to around 15-17k.
For PVE, this isn't a big concern as most teams have complementing builds by proxy, even via MM half the time but its up to what you feel comfortable with.
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For me, my sentry/savage gloves build has 3700 firearms, 398k toughness, and 31k SP which is fine for me, I reduced toughness for firearms.