Hey, thanks for the feedback!
At 8:42 I did use Alt+S, and the header shows the shrink/fatten options during the operation. If that makes it uneven you could try bringing out the sides manually by setting the orientation to Normal and the pivot point to Individual Origins.
I added more detail at 9:49 since during the game you’ll have to unload and reload the clip, so that part will slide out and bee seen.
Hope that helps clear things up! If you have any other questions, just let me know.