Ramazith

You could just follow the DK guide on TWINKDB (I assume you are talking about UH dk since I could be of no other use to you than on that spec).
TBC 3x socket (or MoP heirloom) should be your weapon of choice.
Either go full vers or ignore it, don't mix feverflare and harmonious.
Mastery around 40-60% (with or without pit fighter etc) is comfortable and gives you room for high haste and mid range crit

Yes i did, but i tried to play with mastery a bit and see if its usefull to stack full mastery sinec all my dmg is shadow or not, now i have 60% mastery with 13mastery sword + both mastery trinekts, you can check it here https://worldofwarcraft.com/en-gb/character/eu/argent-dawn/illm%C3%A6tik

Sorry, been away for a bit.

As I said, you could just follow the guide on TwinkDB. I visited your character and would look upon other trinket choices and as mentioned before, it is advised not to go full i28 boe gear and implement some TBC pieces.

First you did not specify what class, second its not worth stacking That much mastery since you sacrifice other stats, you got limite stat buget to go around. Stack mastery to 35% max (since în BG will rescale and go to 30%) then orient yourself towards either haste or versatility.

Crit comes naturally if you use some tbc gear, if not and going full BoE gear, i need to tell the class to see stat priority.

oh, my bad... its Unh DK... currently with all my mastery gear i have around 60%as i said + with 2 trinekts i can get 110+%mastery for my "burst" so thats why im asking if its any good to have 110%mastery on your burst since all my dmg is shadow, or if its useless in pvp :)