Hi --
Not to worry. Styles and registrations are lightweight (i.e., relatively small file size). All of the styles, registrations, voices, etc. on my Genos add up to about 10 Megabytes.
The heavyweight files are audio: WAV format, and to a somewhat lesser extent, MP3 format due to compression. My audio files add up to about 6 Gigabytes.
The Genos backup feature allows one to include or exclude audio files from a back-up. I exclude audio files and the back-up file ("Genos.bup") is only 13 Megabytes.
I transfered the audio files to Genos using "USB Storage Mode," Reference Manual, page 151. This is a relatively fast way to transfer files to and from Genos. It's also a good way to back-up audio files, too. In USB Storage Mode, the Genos behaves as if the internal memory is a USB flash drive on your personal computer. Very handy.
Hope this info helps -- pj