Hi Arthur,
Your tempo and split permanent settings: just follow page 11 and you can get them back at any time from the custom panel, without any disk loads.
If I understand you correctly, the custom style can be altered by copying to composer, changing the registrations and anything else you fancy, and copying back to custom. follow the middle of page 42 about the direction switch.
If you want to save and load a single custom this is all on page 41.
Then have a go at Lindoz's tutorial...