Wow firehand10k, this sounds like an awesome project..... and with 2 Scorpion hilts + the Flamberge bits it will be HUGE
I would guess the colour of the crystal won't give enough colour to light up the way you want if you used an AS LED below it, just a guess tho..... I have a couple of LED bases that I sit a large crystal on top of, and the colour of the LED's determine the light up effect, mind you my crystals are mainly white quartz.... Best bet would be to take a saber with AS LED with you when crystal shopping, with no blade and shine thru the crystal to see how it looks..... even with a real amethyst coloured crystal I would guess it would still look very white with AS..... perhaps take a VA along too, just to compare......
I'm only going off what I'm guessing tho..... I have seen those salt crystals that are different colours with white LED's illuminating them.....
Also, I'd guess the flatter the bottom of the crystal is, at the connection to the LED module, with the least amount of light leakage, would give the best illumination.....
I also look forward to seeing how you go with this....... lots of pics would be very much appreciated........ cheers +1