Well, I forgot to mention that I already made use of the geomantic sorcerer mod(installed before my megamod BWP installation) and just transferred the global affect to my normal game(and changed the 85 figure to 300). So, everything's alright now and I'm getting triple XP for my triple-classed characters.
I disgaree re the game being ridiculously easy, as a result, though. IMO, it's way too easy, right now, without triple-xp, as one can simply go into a dungeon, clear 2 or 3 rooms, use up all one's spells, then go outside, rest, and go in and take down more monsters, repeating the cycle(with no new monsters appearing). That tactic (which most people use) makes the game way too easy. I prefer not resting at all when in a major quest area, expending most if not all my spells, and that's only possible if my spell-casting characters all have enough spells to cast(and therefore enough levels). Plus, I've already made hostile npcs/monsters far more effective as I've installed max hit-points for them - plsu I have scs/scs2 installed etc.etc.
*What found ridiculous is that after doing the entire trilogy (with no big megamods) I only reached c.24th level, after doing every possible quest. With just darkest day installed as well, that rose to only 26th level. With triple-classed PCs, I'd quickly get nowhere.