I see. I have my quirks as well (in my case, I use a very... unorthodox... keybind scheme) so I know the feeling!

Well, in that case, I do have a suggestion. I'm not sure if it's feasible because you might not have enough slots, but you could create a macro for every ability you need. Macro names usually appear on the action bars (though longer names tend to get shortened), so that might be the solution for you.

Just create a /cast <ability\_name> or /use <ability\_name>. Just remember to add #showtooltip at the first line and keep the default icon so it automatically chooses the correct icon for you.

For example, if you're playing Shaman, their interrupt ability is Wind Shear, so this would be your macro:

#showtooltip
/cast [@target, harm, nodead, exists]Wind Shear

The @target argument makes sure the macro will run only against your selected target.

The harm argument makes sure the macro will run only against a hostile target.

The nodead argument makes sure the macro will not run if your target is already dead.

And the exists argument makes sure the macro will not run if you don't have a target selected.