Hi, i was looking at some gas engines and was wondering a few things.#1 I saw a cox engine that said "25% nitro" does this mean oil or what.#2 What is the mixing of oil to gas for nitro engines?#3 I was looking at a couple of "vintage" engines on ebay. They did not say anything about gas or glow. Are vintage engine gas, glow, or both? Thank you so very much!