[support] Complex CCK data type - multiple fields

Hi, How would I go about building a complex CCK data type? The one I have in mind might be e.g. the different formats available for a "book" node: Format Width Height Depth Weight ---------------------------------------------- Hardback 15cm 24cm 2cm 14oz Trade pback 14cm 22cm 1.5cm 10oz Paperback 10cm 15cm 1cm 6oz Should I store each row as a flattened text field with delimiters e.g "Hardback&15&24&2&14", and let hook_widget() unflatten it prior to editing? Or can CCK store complex data types unflattened? Given the form chunk to edit each row would be five input fields, can hook_widget() cope with making this whole block "multiple" easily enough? Would it need to be defined in form API as a multiple'd fieldset? Cheers, J-P