Spinning down my hot spare

Hey. I have 6 disks in a raidz2 and one as hot spare.

I was wondering if it would be a good idea to have the spare spinned down, considering it shouldn't be under any load. It would save some extra watt and also be quieter. I have no experience in having my disks spin down so all advice is welcome.

Second (probably noob) question: if an of my disks fail and the hot spare gets promoted do I have to manually disable the spin down?

Thanks a lot