Need an advice for drip tip

[elkabungo]

Hi,

I have few questions.
1. I'm using a vivi nova tank and I need a drip tip - which one would you recommand?
2. Using an Ego-c - which drip tip would fit to eh standart cone?
3. what is the type of Battary the ego-c uses? - is it 510 or other type? need to know because I saw the most drip tip fit to 510 or 901 type? so How can I know?

Thank you,

Elkabungo