Yeah the manual editing will be fine on a Mac.
If there are a lot of people who want a Mac version of the editor then post here and let me know - I can probably make one fairly quickly ... a week or two most likely (the GUI libs I used to make it are x-platform, I just didn't have a Mac upon which to build and test it to be frank).
This editor is largely an 'experiment' as no ones really ever released this sort of thing for a console game before .... so far I'm really pleased with how its been recieved by everyone so