Technically Comet bulbs are AC/DC so will work with both voltage types (only on one direction with DC)
12v will make them pop quickly though, it’s far too high voltage.
Are you just wanting to add more lights to the game? If so, just connect to to existing GI.
Stuff plugged into Jim’sMod Power Bowles will come on and stay on for as long as your machine is turned on. It will illuminate them before the rest of the lighting. This is almost certainly not what you want from an aesthetics point of view.
You’ll be slightly undervolting the bulbs too, so they won’t be as bright as they could be.
If your replacing the bulbs with LEDs throughout then the GI circuitry will be under a fraction of the load that it was originally rated for, so there’s no worries there.
As said earlier things like speaker light kits and anything else that either wants 12v/5v and would usually be plugged into the Power Board to get it is a good candidate for sticking on the mod board, like you’ve discovered with ColorDMD