Diablo – What are the chances to drop the Boon of the Hoarder gem

In my opinion, the best place to farm gems quickly is act 1 inferno. In act 1 inferno, flawless squared gems are dropped, and those are the highest gems that can be dropped.

If you'd go to act 4 inferno, the same quality of gems would drop, but the pace at which you could kill enemies would very likely be much slower. Stay in act 1 because monsters are relatively easy there.

Obviously, keep your eyes open for resplendent chests and treasure goblins, but that goes without saying.

No, the way magic find works has no effect on items like the plans for staff of herding. Also taking off nephalem valor would not affect the outcome either.

The way magic find works is once the type of item that will drop is chosen it increases the chance that it will be a magic/rare/legendary/set item. But since the plans for staff of herding is most likely in its own category, it can not drop as anything other than it self and Magic Find will not effect its drop chance.

The difficulty you farm in does not matter towards your chance of getting them, it is just a question of how fast you can kill the boss or maybe get xp/usable loot while doing it.