[eschwartz]

You will need to use a custom column:

program:

sizes = formats_sizes();

ifempty(
	select(sizes, 'AZW3'),
	select(sizes, 'MOBI')
);

This will return the size of the book in bytes, preferring AZW3 over MOBI just like the device driver.

You will need to add up the sizes manually, as custom columns are not aware of the metadata for other books.


Or for Kilobytes:

program:

sizes = formats_sizes();

final_size = ifempty(
	select(sizes, 'AZW3'),
	select(sizes, 'MOBI')
);

kilobytes = list_item(
	divide(final_size, '1024'),
	'0',
	'.'
);