Hey there sorry for the late reply, as far as I know you no need to balance the SKILL reward on each of the music lesson. You just need to focus to add more LUCK on your production lesson. If you can, try to maximize your potential SKILL reward , make it until you only need to do two or three music lesson in a day to cover your total EGO gain on that day.

This will keep your EGO meter in its minimal value.

Doing two or three music lesson in a day is much more better than doing a whole day for two or three days straight for music lesson. As long as your can maximize your STARBITS gain in a day then its good.

But this is just my strategy for playing. you can try to explore more strategy and decide which one suit you better. :))