A few points for you to consider for your safety, the LiPo cells were installed in this
mod for their high drain - high amperage specifications.
You did not mention exactly what 18650 you are using, but if it's 3100 mah, it sounds like an ICR low drain model, not even a very good choice for a Vamo.
Lastly the charging circuitry in your mod is designed to charge a LiPo cell not a standard 18650 cell, the amperage may be too much to safely charge the battery in the mod, or use it as a pass-through.