Great script grue, thanks!
Just a little thing though, when I tried installing and using the script it would tell me 'Failed to give merit' whenever I tried to reward it. I found that this was a session error due to how you get 'sc'.
I've made a small fix here (on lines 12-14), which works for me currently:
//get csrf token
var sc = $('input[name="sc"][type="hidden"]').val();
sc = (!sc ? ($('a[onclick]')[1].href).split('sesc=')[1] : sc);
Getting the same error, great you already spotted and fixed it

Also, very well done grue, the extra page to open when giving merit was one of the most criticized aspect of this change.
Thanks!