Yep, its a wireless, and from that singular judgment we can assume that you wouldn't be breaking 3v going through there at the absolute maximum, as for solder points I suppose your best bet is to use a multimeter to find a decent spot. Also, I'm fairly sure that the ring of light mod on there would be the same as the ring of light mod on the console, possibly with smaller LEDs, but not definately. I'd say you'd probably use quater watt LEDs at most (no idea on actual size), the amount of voltage and current going through there is going to be miniscule.
*toe* Hopefully I helped
Edit: Oh yeah, just as a addition, you wouldn't see more than 5v going through a wired control at most, as the USB Standard (which these controls adhere to) has 5v +, but I cant remember the PIN offhand.