I probably should have said this earlier.
Please do not release 64-bit add-ons.
If you want to beta test your add-on in 64-bits, great! If you have gotten 64 bits working, that’s totally cool!
But, please don’t ship 64-bit code. The problem is: we are still in beta and there are still open issues with 64-bit plugins that have not been resolved. If we make changes to the plugin system during beta to make 64-bits work right and your add-on is broken, you won’t be able to react to it if it is already released.
So wait – make sure to test against the RC. Like new features and scenery file formats, while the new features is in beta, it is unstable and we’re not going to try to ‘protect’ you from change. Once we go final, things will be set in stone but we are not there yet.
(In beta 3 we changed our address space layout on Mac…that should give you an idea of how new this stuff is.)