My service manual (Suzuki) says it's a 540 Watt alternator. That translates to about 38 Amps @ 14 Volts (with the motor running).
There seems to be plenty of reserve. With my handlebar heaters on "high" (35 Watts)and my electric jacket liner on full heat (70 Watts)my add-on voltmeter shows I'm charging well at just over 1500 RPM. Adding the brake lights doesn't seem to be a problem either, and I have two auxiliary brake lights on the back of the bike.
I've never measured the current draw and wattage of each piece of the system, but you can estimate it. Figure about 60Watts for the high beams, another 16 Watts for the two tail lamp bulbs, add in maybe 120 Watts for the ignition system, a few more watts (maybe 30) for the various relays and you can see you still have a bit of headroom.
Ride warm and enjoy the heat.