Hi!
I have a different solution, not necessarly better. I did not know of Alt-V option to show the extended toolbar though. It is better to have the “toolbar” icon present for some (who can’t remember to press Alt-V shortcut). I’ve written about it here: https://www.mihavalencic.com/?p=7.
In short, just add wp_adv before the rest of it. So line 57 would look like:
theme_advanced_buttons1 : "wp_adv,<?php echo $mce_buttons; ?>",
Miha