Last time I looked into it, creating Mac installers was not simple and required special software. I can only imagine that this has gotten worse as Apple continues locking down the Mac. The default settings won't allow for installation of any software not approved by Apple.
As for the TYP questions, I don't really know. But how big are your maps? Considering the speed of typical internet connections, wouldn't it just be simpler to create separate versions? That also makes it easier for the user.
Another option might be have them download the free TYPchanger program. It's dead easy to use, but some non-technical people might still be put off by this.
http://www.javawa.nl/typchanger_en.htmlBTW, everyone should be using GMAP files for windows now too, since the new version of Basecamp/MapInstall doesn't work with registry maps anymore. The tutorials on this site really should be updated to reflect this new reality.