I honestly have no idea how hard this would be as i fail hard at programing. Hell i cant even program a turtle... but i digress.
If possible could you make it so server side configs override the client configs so that users do not have to be mailed the config folder in order to enjoy the settings the server recognises. For example i am running a Feed-The-Beast server but gregtech is considered annoying by my users, so i of course disable its functions in the config, however without a clientside config update they cant properly find the correct crafting recipes. As i say i have no knowledge of programing so if its not possible i don't mind, but it would certainly save the hassle of having to send 27+ emails every time i update configs.
Thank you for taking time to read this, I do hope it made sense as i have a tendency to ramble and am normally quite bad with grammar and sentence structure.