I have been working on a little application for a couple months and feel pretty comfortable releasing it here. I think there are some good examples of using custom masked textboxes, and creating a custom file output, input format (not xml :P) It calculates 10+ different commonly used oils for making soap, and I have made several batches now. You can run the application as admin to register the file type in the directory you decide to run from... there might be a better method to handling this, but it works for me. Thanks to BrambleBerry's source for the conversion ratios!
I realize the policy of no executables, but if you would just like to download the most current release you can find executable here:
Have a great day