"Noob mistakes" usually happen if you rush things. You will make mistakes from time to time, that's how you learn. Once you level and re-glue your first insert, your confidence will grow. When the playfield is completely done, you will notice the difference visually, and also it will play better. It is not "extra work" - it is "extra fun". STOP when it's not "fun" anymore. Take a break. Then come back to it. Pinball restoration is a marathon, not a sprint race.