Donny, the advantages of using a full bank of registrations per song is it provides you with all the features you have been complaining about for years. If you recall, you are always saying Yamaha should incorporate all the features of the SongBook. Well, by using a single song per registration bank, even if you don't use all 8 buttons, you get an alphabetical listing of the songs, the ability to access the lyrics, midi files, MP3 files, transpose, and much, more than the Song Book can do. A single push of a button is all it takes to access all those features.
Now, this takes no more work than setting up the MFD, and several performers on this forum use this technique. Eddie Shoemaker has been using this for decades, and it pretty much eliminates dead time between songs. I, like you, use the eight songs per bank technique, utilizing the default OTS voices, or using my custom voices, but unlike you, I use registrations in conjunction with the MFD, which has been very effective for me.
From my perspective, creating an MFD and registration banks are part of the fun of exploring any keyboard. It allows you to use your creativity to the fullest, selecting every song's component and making each and every song your own creation.
One of the ways I did this was to listen to each and every style in the keyboard, listen to the various intros and endings and OTS voices. I rarely find a style file that doesn't trigger a song in my mind. Then it's just a matter of taking that song and putting it together in a registration or MFD. It's not difficult, and takes very little time. Before you know it, you'll have a well programmed keyboard that is finely tuned for each and every song in you know. This allows you to quickly select all the settings for nearly every song that someone may request, all at the touch of a single button.
After creating a few banks of songs, I strongly suggest backing up those banks on the USB drive. There's no such thing as having too many backups in this business.
All the best,
Gary