qiime feature-classifier classify-sklearn _ Which are the best parameter's values?

splits the query sequences into smaller batches so that only a few are read into memory at one time.

A smaller number leads to less RAM used, at the cost of a little more time

The number of jobs to run in parallel. More jobs = more RAM but less time

There is no "best", since it depends on system specs, datasets, etc... but if you are getting memory errors use 1 job and a smaller batch size (2000?) and just be prepared to wait a bit longer for the job to complete.

Good luck!