Yes it can be fitted
Result is better focus. If u change the bulb as well, you'll get brighter light
Bigger battery will not be needed, but you need to add two relays in your wiring. Any good electrician can do that for you
It all depends on what you want from your light. If you need better focus only, then simply changing the headlight assembly will be enough. Get yourself a new honda 100 or used suzuki gs500/ honda cb250 headlight. Keep your stock bulb (but make sure its original)
If you are comfortable with the focus, and just want a brighter light, then simply get an h4 tube, and let the electrician fit it in your existing headlight. Tell him to add relays as well
If you want to change both focus and brightness, then change both along with the rectifier