I really like "spellbinder" for binding my macros to the g15 mapped keys. Since you already have have key strokes saved it is really easy. The addon lets you select the macro/spell/item and then hit the bind button, press your G key and save it.

Now you can hit your g keys and the macro executes without using up any action bar space. The bindings all go into your bindings file in the wtf folder so you can edit them offline.

With my really lame 2-3 box set up this works well.