When adding to config.ini, it seems to be possible to add a value.
For a text type, I might have number_of_thumbnails.value = "10" but that value doesn't seem to be reflected anywhere.
Similarly, for a checkbox I might have show_search_summary.value = "1" but again, this doesn't change whether the checkbox is selected by default or not.
Is there some good documentation for theme options set in config.ini.
Also, is there an option for a number input type rather than text?
Omeka just uses the built-in Zend Framework stuff for configuring the theme forms. Theoretically this should mean that the Zend Framework docs would the place to go, but they're sometimes more confusing than helpful. Everything in the main [config] section of config.ini will act like it's specified under the "elements" key. It's not really obviously noted on that page, but pretty much everything about an element besides type needs to be set underneath the options key.
So, a default value is set with .options.value, not .value. Note, though, that defaults will only get used if there's no already-saved configuration for that theme for that element.
Zend Framework 1 doesn't support the new HTML 5 form input types, so there's a little Omeka addition to allow them. For HTML 5 input types like number, you can use the type "input" and then specify the specific type you want with .options.attribs.type.
Brilliant, thank you.