This might be a much more efficient way of doing it than my method in all honesty. I'm not too familiar with the Logitech macros. I'm just not sure if you can actually mimic the building mechanics the same way with this method. For example, let's say you press your stairs button, but instantly want to build walls, then stairs again... does it work this way? I'm intrigued
Well, each build button is set to build and return to weapon. I can press the next button as soon as I see the weapon coming back out animation. If I press it before then the macro won't work. It all happens very quickly and I rarely hit the next button before the previous macro is finished.
I wouldn't say it replaces using the old building method if you are doing a multi-level base while not under fire etc, I would say these are more for the quick, panic, underfire building of walls and walls/stairs for cover and combat. I still sometimes use the old build method also, it's bound to my mouse wheel press.
While it's not PC direct bind level efficient it still works extremely well, especially for not having to buy/use an extra device. Give it a shot and see how you go. Remember when you are recoding your macros in the mouse software to record the delays also and press your key combos as quick as you physically can. It took me probably 4 or 5 goes to get it all timed the way I wanted it.
Hope you can get it working to your liking.
Much luck, bro.

What? I thought you can't use onboard memory for macros unless plugged in directly to computer?
Yeah, I also read that, but it works perfectly on my G903.