Just playing around with the workbench andjust discovered that if you put a qixoni ceystal on the same saber as a solari crystal, the dark side only and the light side only limittations cancel each other out. Now I've only been able to test this on my assassin character but I imagine it would work for LS players as well as middle men.
If you think about it, this is a pretty nasty combo because not only do you get DAM +8, ATK +3, and FGEN 1, but since you fight sith a lot - i hope this doesn't count as a spoiler

- you get the +1-8 vs. DS. Throw in a couple butt kicker upgrades like a diatium cell for DAM+5, a deflection emmiter for BBD+4 DEF+1, and a pontite lens and you got a main hand saber that has....
DAM +17-47
DAM +1-8 vs. DS
ATK +4
BBD +4
DEF +1
Then for some kicker, my short saber had my character's chrystal and a stygium crystal for stealth & dex, but really it's cause i didn't have a kaiburr crystal. Throw a couple upgrades (Super Discharge cell, Ex Deflector, Ossus Lens) and boom. Marauders die in two flurry swings from an assassin with 14 strength.
Then just because I had more force points than I could spend, I made a switch set of sabers with 10 and 15 BBD. Just to run around and collect baddies on my tail and literally have huge piles of bodies. It's funny. You just let visas and mandalore faint on the ravager and run around to try to get as many sith as you can into one room... then force storm!!!
It's almost as bad as planting mines in stealth mode.