For text imported from a bloompub file formatted in RAB as "Bloom Book - convert to Picture Story book, The font size and line spacing will not change anything. When we first imported the books, both the font adjustment bar and line spacing adjustment bar, successfully adjusted the line spacing but did not change the font size. But if anything in the book htm file is edited, then the line spacing adjustment no longer worked.
Perhaps the importing of bloom format does not support font size or line spacing changes. Changing any style settings in RAB has no effect either.