I think the batteries peak output measurement is defined as CCA - cold cranking amps. - that is a useful value when the starter is turned. If you have so many lights that you are going to draw as much current as a starter then a psychiatrist is in order not a bigger battery - just saying....
What a lager capacity battery will do is run more devices a longer amount of time then a smaller capacity battery which will run those devices but for a shorter amount of time.
A bigger battery will help keep your bike running if the stator cannot keep up, but on long rides if you are running off the battery and not the stator then it can be thought of as not having a charging system - eventually your battery will die, ignition will fail and you will be stuck.
Actually a better idea instead of a larger battery would be a stator custom wound to produce higher output (if somebody is able to do that for you - i do not know)
If you are going to look into good batteries though - check out http://www.odysseybattery.com/
their specs are what I consider to be pretty good, everything I own has one of these batteries in it, never an issue.
If you go one short rides and charge your battery after every ride then the extra lights are ok, even with the small battery, the only thing the larger battery will do, if you are past the max output of the stator is give you more time between necessary charges - i hope this helps. BTW, if you are past the max output of the stator all the time I think you risk burning it up, I have been past my max output a few times, and still have not burnt it up but I guess it is possible, I thought it was fused though so what the heck right?