This script will alter your MythWeb status page to display disk usage in GB instead of MB, and also display space used and space free as a percentage, and display the estimated number of hours of recording time left, from your maximum recording rate to your average recording rate.

Note: you will need to customize this script before you can use it successfully!

To do this you will need to edit the script from greasemonkey and replace the values for the two variables at the top of the script (avrate and maxrate), with values obtained from your mythfrontend status page. If you have made a large number of recordings, these figures shouldn't change too much from time to time, I suppose.