Minimum acceptable self-launch climb rate

The Arcus is not an Open Class glider.

The Arcus E may not be strictly "Open Class" I don't know the strict
definition of "open". But the point I was trying (unsuccessfully) to
make is that the 20m wings are heavy maybe even heavier than
some true open class traditional gliders?
Anyone who has tried to pick up an Antares20E wing will understand.
Arcus E wings have 72 batteries plus associated mounting hardware,
each battery has a heating mantle, there are control electronics
boards every third battery plus the wiring & cooling hardware. As far
as I know it has exactly the same system as the Lange built Antares
20E. (Lange built the "E" bit of the Arcus).
Each battery weighs a little over a kilo so the whole lot possibly
weighs 80-85 kilos, add two pilots and you get high wing loading.
I understand the Arcus with full water ballast is pretty predictable;
maybe a pilot with Arcus E experience could comment on the
handling characteristics.