Use batchSize parameter

[LJNIC]

Is there a reason the batchSize parameter isn't overrideable via configuration?

[bashir2]

The main reason is that we try to expose minimum number of config params in the controller configuration and we thought batchSize tuning is not that important. That said, there are some recent evidences, like #1104, that contradicts that assumption.

Please feel free to expose this in the controller configuration, if it matters to you (and ideally provide some context/data describing why it matters to you).