It s best to wait for desired headings to be added. New headings are listed regularly on Curriculum Corporation s website. Suggestions can be made for new headings directly to Curriculum Corporation or through your state representative. Most cataloguers will want to add more. General texts in, say, Geography often require up to thirty headings.
Specific headings yielding around ten hits are probably more satisfying.
On the other hand, a general heading would give the user an indication of the location of resources on the topic, where a search of table of contents or index would yield the desired result. For abiding combinations of subjects, Departments or Topics could be used. Depending on speed of hardware, a combination of thirty headings with OR in AfW is quite feasible. General opinion is that these add useability to the catalogue. Clicking on this combination directly lists resources for the preferred heading.