OptionalchunkMax participant accounts per settlement chunk (the lock-width bound). Default 16.
OptionalmaxAccepted movements per journal batch; the batch commits as one insert. Default 64.
OptionalreservationsThe shared cross-session registry; a private one still guards within this session.
Session tuning. The batch and chunk defaults are sized to the engines' contention profile; the one option correctness rides on is
reservations— every session in the process shares one registry, or its accept screens race each other.