Here's how I have my GKeys working in WoW with Octopus.

Firstly, my broadcast key is 1 on the numpad. This can be whatever you want to set it to, I personally kept it something I'm not likely to press while on the main section of the keyboard since I usually just alt tab to fix any errors with my alt.

Next, go into the gkey profiler, select one of your keys (for example, G1) and instead of doing assign keystroke do assign macro > create new macro. This will bring you to a little window where you can create new macros (if the program has picked up your installation of WoW you'll likely have many more similar macros you can assign, ignore these for now, however some are quite nice to remember). Create a new macro, name it something logical (for example, Octopus G1) and then start recording a keystroke. Ensure record delays is unchecked, then firstly hold down your broadcast key, and make sure you hold it down for the duration of while you're recording the macro, or else it will not work. After that hold and release your keys so that it looks something like this:

v NUM 1
v CTRL
v ALT
v F1
^ F1
^ Alt
^ CTRL
^ NUM1

Repeat process with as many keybinds as you think you'll need (I personally lost interest after doing the initial 18 keys...) and then bind them ingame using Bartender etc.

Happy dualboxing.