The 10% nitro should be fine. Most likely,you'll never notice a difference even though by the time your done adding oil,you gonna have even less % nitro. You'll notice WAY more of a difference from the oil content etc. then you will the nitro content......and even then,I doubt you'll notice a difference. I'd just put some oil in it and try it. You might need a slight re-tune of the engine...but thats about it.