Glad your menu now does what you wish. As GRUB 2 is upgraded you will have to re-edit the file to include the change you made. This is not to be confused with running "update-grub", but when a new version is released and you are asked if you want to retain your current version or accept the maintainer's newer version.
Yes, G2 is very powerful. The scripting language is not complex but is something an average non-IT user isn't used to. For example, I am an average user and not well versed in programming languages. Every time someone asks how to hide something, I have to experiment with "cut", "awk", "sed" and other commands until I can come up with the correct output. Sometimes it takes me a while. Users with programming experience can easily do these things in a very short time. Those of us without such experience have to rely on others or take the time to figure it out.
The good news is that, because of the power of Grub 2 and the basic way in which it works, there will come a day when a GUI app will be able to do all these things for us. StartUp-Manager 2 or some other app will be created to do all these things via menus in an easily-understood graphic application. We'll just have to get by with editing the scripts ourselves until that time.