a better and cheaper way would be to find a google+ scrapper may be you find it for 50 dollars MAX, go to your competitors videos and the comment section run the bot and make a list of those google+ accounts and use that scrapper to then follow every single one of them and ofcourse you can email these G+ profiles even, not only will these be REAL people but also targetted groups of people that will follow your content cause they are watching same Niche day in day out on your competitors channels, also additionally you will have an ability to interact with so many people cause remember Youtube is a social platform not just posting videos i seen people really just focussing on commenting on other channels videos all the time even other people's google+ profiles this creates that community feel to it you should try it. If you find a cheap google+ bot please let me know as well cheers
Thanks for suggesting this method. I might try it with a little twist.