MergerFS: Which policy is the best for my usecase?

I want to use the mergerFS-Pool as Mediaserver containing large files in different directories and I don't want to care about where I have to create new directories. If possible I'd like to use the drive on which a directory first was created and write to exactly this drive until it is full and then automatically mergerFS creates right this directory on another drive in the pool where most space is available.

This should prevent OMV to spin up all drives but only the drive I'm working with a directory.

Am I thinking wrong here or is there a perfect policy for me? Which would this be?

I'm thinking about changing the policy on my mergerfs from mfs (Most Free Space) to epmfs (existing path mfs).

But how can I create a new path on a specific drive in the pool?

An I wrong thinking that this is only possible when sharing every single drive of the pool and create the new path on the desired shared drive?

Merry christmas by the way

Quote from gderf

Explain why you wish to change policy.

To create a new path on a specific drive you must create the path on that drive, not in the pool.

I do not understand your last question.

I don't want to spread paths over drives but want to "control" an which drive which path is created and used.

The last question has a typo in the first word. Should be Am instead of An