I would go with acuity to be honest. for both pve and pvp Its a really nice set. Its especially good on a stamblade where you can really focus your burst in that small time window to get the most out of this set, meanwhile something like a stamDK with more sustained damage would benefit less from it, but that still doesnt stop stamDks from using this set, so if this works even for them, it should also work for stamblades.

That being said I don't see that big of a difference between hundings and acuity. If you have one of two already crafted, then use it, If you don't then craft acuity. And I'm no stamblade expert but for pve I would pair it with war machine , as its just a no-brainer synergy for stamblades and their cheap ultimate provides them great uptime on it.

And about trials, Its harder than vet dungeons , but not really that hard Its actually very easy and fast when you do it with a trial guild instead of some random pugs.

Hundings - Spriggans works for everything.

Normal trials are really enjoyable actually.. Vet though ergh.

I think acuity is worse on stamblades since they have such high crit that you can pretty much just crit just as much with a normal build. Plus its a thing you have to practice to use well not just settle into a nice rotation.

Twin Fang Serpent and WarMachine with Maelstrom Bow is still the meta build I am pretty sure. Its basically just an upgrade over Hundings Spriggans. But in all trials gear.

When I compared Acuity with Hunding's months ago on my Bosmer Stamblade it seemed like Acuity was a little stronger.

https://forums.elderscrollsonline.com/en/discussion/374084/mechanical-acuity

It has since become a little more stronger as my rotation changed over the months to squeeze more DPS into 5-6 seconds. It pairs well with Spriggan's if you don't run trials.