With my current gear equipped, the sims from Raidbots is telling me to use only 2 pieces from the S3 tier set: head and shoulders. If I switch some other pieces around, it still tells me to use only 2: head and pants. No matter the talent tree choices I pick, it still tells me to use 2 new and keep 2 old. What to do?
Does it get better with higher item levels? Also, what talents are we suppose to go with to get the most out of the new set?
Edit: sorry not bloodmallet, sims from raidbots.
Do you actually have 4 pieces for the new 4 set bonus, you only listed 3.
I have two pieces of the S3 in my bags, the head and shoulders. However, on Raidbots you can convert any piece of valid gear at any item lvl into a set bonus and sims it even if u do not have the actual piece in your bags. I have some champion pants and gloves in my bags that can be converted via the catalyst. I listed 3 because it never gave me the suggestion to use the gloves.
So just to clarify. Did any of the sims it showed you use all 4 pieces of the T31 set? Better yet link the sim here.
It did not, not one that was above my current dps range that is. And I ran the sims yesterday. I did not save it. I can run another, it will take a few minutes.
Please do, or paste the input code you get from typing /simc in game so I can take a look for myself.
Just realized that my talent tree in that sim is not the one I currently use. I was playing around switching talents to see if I could get the right combo for the full 4 set, then got frustrated and just logged out. lol
You have the sim set to only expend one catalyst charge when creating combinations. I ran it for you.
OHHH! How do I change it? Omg, so sorry, not to savvy with the sims stuff.
It’s above the item list when you run top gear.
OH i see it now, I was not aware that would impact it like it did. Thank you so much!
You are the best! 
What talents go with our new set?
The build I ran was for ST: https://www.wowhead.com/talent-calc/priest/shadow/DAREEAVFFEBUFEKFSKBQCBQNVFFQVFGSVFghBBR
Dungeons something like this:
Maddening touch and mind devourer are somewhat interchangable if you want a bit more ST or AoE, also if you’d rather play spike you can drop mental decay and voidtouched. Really as long as you keep the capstones and core spells you can play around with it a lot.
Thank you so very, very much! I was at my wits end last night trying to figure this all out. Spent 2 hours reading and reading the forums here for answers. You are wonderful!