I tried the GS coils and it was really better than CS as taste was good and you can easily go in highest wattages.
BUT with using them i had problems (gurgle/leak), they really look identic but must be a little bit different...
Someone from our forum got a good advice from a vendor to use CS coils.
Remove one of the 2 pieces of the filling material, with just one piece i have no burn taste and it is really better for the moment.
To easily remove the top of the CS you have to let it attached on the base.
Sorry if it is not really understable, difficult for me to try to explain in english.