From what I gather, the only thing that you have to worry about is if you're running an electric start. If you have a kick-only bike you should be fine running basically anything (besides heated grips, etc), and can use pretty much any battery (within reason). Mine is for a 50cc dirtbike to put it in perspective.
I have the 7" headlight, and although I just switched all my signals to LED's, I added resistors so they still draw as much current as the stock incandescent bulbs. I'll be adding some decorative LED's shortly, and I'm not worried about it whatsoever.
That said, if my bike is on, but not idling, there is very little power going to the lights/etc... headlight dims a bit and turn signals will light but not always blink. The small battery is to get my bike running, and from that point on the bike is essentially powering itself.