You can easily discharge using your model, so a discharger is not necessary.
Its pretty common to stop flying not far from the 3.7 v/cell (at rest) recommended storage level for LiPos.
Also note that this is a storage level... If you are not storing for more than a month its not going to make much difference if you leave them at LVC cutoff, some random level or fully charged.
Keeping the packs cool is more important. DO NOT store them in your car in the summer. Room temp is good. In the fridge is better.