All we're talking about here is a MOTD to be displayed upon login.

While this has the same effect as sending a message to every country it is distinctly different.

Where you display this MOTD is entirely up to design limitations.

To me the easiest way would be to just use the page when you login that says you've earned tour 6 bonus turns and add the MOTD there.

EDIT: I should also add this is a good addition but only for the clan mates who are lazy and do not check their alliance site prior to running turns. As long as I've ever been in an alliance it's always been best practice to check your clan website before playing your turns to avoid missing out on a command/instruction from said alliance. This is for the lazy people who do not do this :p