Storage mode: what percentage?

[Roadrunner13]

...a frequent source of interruption on a 120v service is the GFCI circuit that can trip for a myriad of reasons under "relatively normal" use, requiring manual intervention....

This ^^^^
You can not leave the car without someone readily available that has some electrical troubleshooting skills if hooked with 120V cable.
Being away with 120V cable is bricking waiting to happen!!!
...and storage mode just makes everything so much worse.

OVMS does have a notification mechanism when SOC goes below a value that you set in the feature/parameters screen.
This can also be used if you're not paranoïdly checking your apps daily when away from your roadster
Of course my car is in the shop today, so OVMS is disconnected and I can't tell you which parameter exactly tonight...