Is it OK to open up the center hole on a 3-up XPG star, as long as I avoid the obviously conductive area that I should obviously be avoiding in the first place? 
Yes. :)
You should be able to see the traces on top of the pcb...just avoid those.
Thank you, Match.
You’ll want to make sure the screw head does not scuff through the solder mask if it overlaps those traces. Maybe use a fiber washer.
I did just that last night to mount a 3xNichia 219 star into a LED desk light that I am modding.
I used a small shoulder washer designed for mounting to-220 transistors to heat sinks. They are designed to keep the mounting screw insulated from the tab on the transistor. Something like these: http://www.ebay.com/itm/20-Pcs-Special-Nylon-Shoulder-Washers-4-Screw-Mi12SWS0197-/271001113740?pt=LH_DefaultDomain_0&hash=item3f18ecd48c or these: http://www.ebay.com/itm/50-x-TO-220-Transistor-Plastic-Washer-/280988964021?pt=LH_DefaultDomain_0&hash=item416c3f54b5
I had to slightly expand the hole in the star to fit the barrel of the shoulder washer.
Thanks for the info guys, but I just opened it up to fit the six wires I need to send through the middle.
Wire it like Match does and you should only need to run two wires from the driver.
At most you would need 4 wires. 1 led+ to all three(jumper the other 2) and 3 led- if you are using 1 master/2 slaves. That is if you are using 7135 driver/s.
I decided to follow dorpmuller’s thread as closely as possible (except for the driver) to avoid any issues, as I am not very well versed in the nuances of flashlight electronics, and dorpmuller has already done the homework! :bigsmile: