To be honest, shoutouts don't really do what you hope they do.When you shout someone out in a video, only a small percentage of your viewers will even consider checking them out. I have over 500 subs and tried to shout out one of my friends in a video that got around 600 views and a decent amount of comments. I think only 4 people at most subbed to his channel. Viewers are interested in the content, and that's what you should focus on.