I finished story Im just autoing to get materials since its a hassle. Level meaning rank I assume? Its rank 41, and I used Light units only, I actually bought a 25$ pack on the light banner which gives you a chance of porking out 2 or more light units or if unlucky 2 of the same units.
If you reroll and want my honest advice I recommend rerolling for Light units only, Fire, Water, Earth, Wind units you can get later on but the most rare are light and dark units. Focus on getting either Achel (healing unit) and or Heathbell. If you have money to spare I recommend buying the pack which comes with 1000 stones and a guaranteed unit ticket and used the stones on the light banner. Im sure you’ll go much father with those units.
If your also planning on getting units other than light and dark I recommend going for what units you personally want.