Time Machine towards a NAS

Hi,

I work with a Mac Mini, under Mavericks (10.9.5), and I want to setup a 2nd drive for backups with Time Machine.

This 2nd drive would be an external HDD installed in a remote place in my place, for safety issues.

Indeed, I would like to have this HDD accessed thru a NAS:

- either thru WiFi, i.e. a "RAVPower FileHub Plus with Wireless"

(see RAVPower FileHub Plus, Wireless Travel Router, SD Card USB Reader, 6000mAh External Battery )

- or thru an Addonics box like their "NAS 4.0 Adapter" (http://www.addonics.com/products/nas40esu.php)

The HDD must be formatted with FAT32 if I understand correctly.

Could you tell me which solution will work (or both) ?

Or, what could go wrong, please ?

Thanks in advance, Regards, G.