I’m not sure if this is what you mean, but if you are saying that unless you are doing the amount for that night you should only do one, you are correct. Otherwise, there’s no reason one person can’t do mehadrin min hamehadrin.
You can use whatever kind of candle you like, including oil. My rav happens to hold that our wax candles have a nicer flame than olive oil, but there’s no nafka mina between one person lighting and ten people lighting.