@Kadatherion: The version of epic encounters that you find here will always be the most up to date since Ameranth works on this directly whereas the other versions are compilations that may or may not get supported by their compilers. But aside from any issue of 6man being up to date or not, I would personally recommend that you try Epic Encounters in its native form where you can have a party of 2 to 4 players. The content is balanced for this and will prove very difficult (and rewarding, I hope) if you respect this parameter. If you have worries about excessive difficulty and getting bogged down, there is no shame in running the mod at a little lower difficulty (it will still be challenging!) This way of modulating the difficulty is not nearly as drastic as the exponential increase in power that you would gain from having 2 extra party members, which would make the game much easier.

Yep, in the end I'm doing that. Honestly, it wasn't really about balance or difficulty, but about story: I was planning to have all companions with me at all times to get the most out of their possible interactions, banter and quests in a single playthrough (propedeutic to Divinity 2 which I plan to fully play once the definitive edition is out this August: I was playing it and just got to the end of act 1 when I heard the news, so I decided to put in on hold for the time being and take the chance to play the previous title in the meanwhile).

But I'm seeing companions here aren't nearly as developed and close to being "secondary main characters" as they are in Divinity 2, so indeed a good challenge (and the least possible amount of issues) seems to definitely be the priority.