Is there a way to swap gems for certain encounters? Say for uniques you want to use Concentrated Effect instead of Increased AoE? Set the item and the slot # the gem is in and then set the gems that you wish to toggle for different encounters? I've looked around but couldn't find anything. I do have a little bit of coding experience so I might give it a go at some point. I'm just not particularly up to scratch with C#. Cheers.
I haven't seen anything that would do what you're looking for. Might be something you need to code up on your own.