OVR: I wish I had an answer for you. I've been looking for a decent board tuner in southern cal for a while now. I've found a good ski tuner or two, but they don't do boards.
I can tell you where NOT to go at least. Don't drop your board off at the Van Nuys Val Surf. They say they have a stone grinder, but they only have a belt grinder, and they WAY over grind and leave way too many ptex hairs.
Also when I was stoopid noob, I took my freestyle board to the bev hills Sport Chalet. Later i found out they just hand sanded the board and put a paste was on top, without even a buff! Useless.
Regarding that good ski tuner, Claude at Skinetsports in Studio City is a pro, particularly at boot fitting. He is a ski only guy, but he's probably your best bet for insoles and boot fitting in the LA area. I think he is the only ABB registered bootfitter in so cal. Check out his shop if you have a chance:
http://www.skinetsports.com/
I'm definitely paying the $55 + $30 for the PTC tune, and the wax/scrape by Shaggy. The Madd 168BX I had in the past had a fresh tune by Shaggy, and I have never seen edges so sharp and perfect as on that board. Everyone getting a new Madd should definitely select this option. The boards are no doubt worth it!