Using ethanol extraction in a nitro RC engine is a bit tricky, especially for a beginner. Ethanol can make the glow plug cooler, which might cause problems. Since you're not running the engine at full throttle for long and it's not for long-term use, you might be okay. But keep an eye on the glow plug temperature and be ready to adjust if needed. Also, make sure to monitor how the engine runs during your tests and be cautious of any unusual behavior. Good luck with your project!