Radiant-Toaster-Gallery style sheets

I’ve installed Radiant with Toaster and have added Gallery

At least with Toaster, Gallery doesn’t inherit page layouts, so it looks
like I need to modify the Page Layouts for Gallery which have embedded
styles rather than using the Style page. Mainly I want to add the
navigation back.

This will mean having to pay attention to styles in two places. Is there
a cleaner way to handle this? I’m thinking to move the style information
from the Gallery Layout to its own style page as for Toast.

I don’t have a non-Toaster Radiant installation to compare. Is there a
reason that Gallery doesn’t use a separate style sheet page?

Thanks for any ideas.