There is a style file size limitation on the "E4XX" series keyboards compared to the larger PSR's - that being a little over 52Kb. If you plug a USB flash drive full of style files into an "E4XX" series keyboard, any of those files much over 52Kb will not even be recognized by the keyboard. That is, files that are too large will not even appear in the keyboard's display as loadable.
Newer style files with file name extensions other than ".sty" must be renamed to have the ".sty" extension in order to be recognized by an "E4XX" series keyboard.
As for more than two main variations and multiple intros and endings, things get a bit interesting with the "E4XX" series boards. For the most part, the keyboard will just use what it can, and ignore the rest. BUT . . . . If there is more than one intro, if you intro into Main A, you get Intro 1, but if you intro into Main B, you get Intro 2. The same with endings. If you end from Main A, you get Ending 1, but if you end from Main B, you get Ending 2. Nice ! ! !
The only time multiple intros and endings and more than two main variations get to be a problem is when, collectively, they make an otherwise desireable style file too large for the 52Kb size limit. In that case, in the Utilities section of the main PSR Tutorial website are programs by Jorgen Sorensen and Michael Bedesem for whittling large style files down to size by removing unwanted or unneeded intros, endings, and variations. You can even use them to mix and match intros, endings, and variations, within a given style file, to your heart's content, as long as you stay within the 52Kb size limit. Even nicer ! ! !
Now, all of that said: Alas! The preset styles have only one intro and one ending. Too bad!
Enjoy!
Roy
P.S.
I have limited the above discussion to the "E4XX" series keyboards, as that is the limit of my experience with the "E" series boards in general. However, owners of "E2XX" and "E3XX" boards may want to do some experimenting, as the above may apply to their boards as well.