How to co-operate mod development with developers running different OS ?

[FlawlessHappiness]

'Amn' you really made me happy.But just a quick question, if I develop my mod entirely in Windows and then send it to someone running Mac, then would he be able to install my thing just like in Windows;i.e paste everything in "Custom_Stories" and run my mod from within the game ?, with no crashes or failure or missing textures.

Yes.
Because everything made in a custom story, stays inside the "custom_stories" folder, (Which is the exact same on a mac), there should be no problem.

I own both a windows and a mac, and I've been able to download and play mods on my mac, just as i do on my windows.