There is no straight forward answer to this. The Reason is BiS Trinkets would only work with 100% BiS Gear.
I will give you some insight into my trinkets tho. The Decision bases on SimCraft 7.03-02. Bear in mind this is a stand still patchwerk simulation. I use Chaosblades in the last tier!
I am ilvl 850 with the necklace legendary (all classes).
I own the following trinkets:
850 [Mark of Dargrul]
845 [Tirathon's Betrayal]
845 [Spiked Counterweight]
840 [Nightmare Egg Shell]
840 [Memento of Angerboda]
840 [Faulty Countermeasure]
840 [Horn of Valor]
I use Memento and Faulty since iam with 850 ilvl, before 848 i used Memento and Tirathons which simed higher in SimC. AskMr. Robot still says Counterweight is better but I go with the SimC Values.
Icy-Veins BiS List says: Six Feather Fan + Darkmoon Deck: Domination/ Chaos Talisman
http://www.icy-veins.com/wow/havoc-d...s-best-in-slot
So in the End if you do not SimC yourself and you do not have all the items on the BiS List, choosing the second best Trinket (you have the best allready) will prove difficult.