Once again, phenomenal work, Graham! I'll work on getting this lined up with PlaymoDB. I bet I can make a version with links - at least with the data I have now, which is of course only a subset of what's here.
As I'm looking at it, I'm seeing that you've given them an order, or divided by page, based on by shape: hat ring, then ordered by length; no hat ring, then ordered by length; child/baby; non-standard attachment (e.g. Super 4/alien/add-on). That's what I would do, pretty much! I'm thinking, a more strict length declination would be useful: short (above neckline), medium (above bottom of shoulder joint) and long. So with a hairstyle in your hand, you'll know where to start looking, and be able to ignore the others to narrow down the search.
Colours, too: the subtle variations are a big complication! Photos are super helpful here, so I'm glad to see you've used them liberally. A line drawing in an instructions PDF (or worse yet, a low-res scan of paper) doesn't show the difference between, e.g., "brown" and "red-brown" very well. I know I've got a lot of corrections to make here, and often I don't specify when I can't see well enough to make a decision.
The 35 sets that you've listed with klickies that don't have described hair, I can decrease a bit. (Some have no instructions on file despite PROBABLY having them, like 9503, so we'd need to get those to proceed, for sure.) I'll at least get cropped-PDF images for the klickies without, and describe those that are obvious. I haven't seen any "official" images for klickies since last spring, sadly.