This is what I run: Code: Fury of Combat +2 Flurry Chance / Rank Juggler's Grace +2 Dex Cap / Tier Juggler's Grace II 20+2 Dex Cap / Tier Hero's Deftness +2 Heroic Dex / Tier Arm of the Hero +2 Heroic Str / Tier Depending on gear you could run Eyes of the hunter for Accuracy boost or Vengeful Aura for Attack if needed.
It is difficult to answer your question as "Noticeable difference" is a matter of perspective in a game where the "random number generator" can have such an influence. Solo, you will notice less of a max difference compared to full support with quality individuals who know their class. In the grand scheme of things, any 1 thing will rarely have a massive impact; but the culmination of all the ones will.
Aye, they're small gains, overall. Especially in the high end, it'd be hard to parse gains in Dex. Heroic Dex works in 25-point breakpoints, so you shouldn't get any of it unless the amount you get will get you to that next multiple of 25, because it's EXPENSIVE to use just for the tiny amount of additional normal Dex. I don't use Dex cap or HDex tribute for the above reasons. Caps and Heroics are pricey, and I don't have the resources. All I use nowadays is Eyes of the Hunter and Fury of Combat, although I'm thinking of taking up AC tribute.
If you stack the Trophy of the Breeding Grounds (+20 HDex and 5 riposte) and the Trophy of the Eye ( +20 HDex, 5 riposte, 20 spell damage) this would bump you up past the 25 point increment, no? Also, the Chapterhouse trophy gives you +20 HStr, which seems worth it. Do zerkers out there run these 3 trophies?