Firstly, yes the UI is not very intuitive and can be frustrating.
One major problem is you can't go back and edit the macros commands, pressing the edit button seems to jump you to the Macro Properties Panel with no way to the edit section.
Fortunately your LG TV keyset has the "sleep" command so I have the following macro. Sleep > Pause 0 > Sleep > Pause 0 > Sleep > Pause 0 > Sleep > Select The first time it worked perfectly 30 minutes sleep timer, so I reset the sleep timer and tried again. Ever since that first go it has not worked. It sometimes stops on 10 minutes with the dialog box left open on the TV, sometimes 20 minutes.
I have tried 20 times now and never got it to work like the first go. What do you think? I have even tested removing and extending the sleep commands to no avail.
Finally, although I like the idea of using the keyboard to fire off the macro's. IMO is this not going to create conflicts if you decide to follow OMP and use the top row of keys for switching your tabs.