cm /ww spec easiest/ best imo, easy to gear for as well, perhaps u should read the cm/ww guide pinned up top and do some searching for gear to hit the mark with that kind of budget, aim for pieces go for about 1 million gold per gear piece spending a lil less or more depending on your luck with item pricing
On a 12mil budget i would spend like 8mil for your cm gear. Using 4mil of the budget just to get some replacement gear for archon set. Dont bother with too much damage modifiers for your cm gear since those are costly! Even if you barely reach 50k sheet-dps its enough. Your job is to freeze mobs as good as possible not dealing the most damage in your party.
If you need some help building your set(s) you can add me on eu servers. Just pm me here on diablofans for the btag.