Looking for stock Alt Tunes, one can re-Flash to stock JTV Models and tunings, but you would lose the Shuriken bundle.
You could use Workbench HD, save the Shuriken patches to a computer, re-Flash for standard JTV models, save those to
a computer, then use Workbench HD to upload Shuriken as desired.
Save Shuriken models to computer, do custom patches, save those to computer, and build a library of what it is you
like to use and load them in when you want.