T12 and T11 2 Piece VS. T11 4 Piece

[:1]Title pretty much says it all, I've done some reading but haven't found anyone talking about this subject.

I recently picked up the T11 Shoulders and can now activate my four piece, but in a lucky twist I also gained my T12 Hands out of BH and with a little grinding can get my second piece.

So is it a DPS gain to drop T11 4 piece for T12/T11 combined 2 piece?

The Tier 12 two piece seems lack luster really while T11 four piece feels fairly powerful.

But I don't raid much on this alt so perhaps I'm underestimating the T12 two piece.

All of this for DW Frost btw, thanks for your opinions.
Thoughts?
Okay then..........
I would recommend using a simulator, but honestly I would go with the 2 and 2.