Hi Ryan, I agree with Moosa here. Thoughtful and valuable comment posting can help you to gain authority among niche audiences, but adding your URL before you've earned this authority is quite spammy and might get you penalised by Google. If I had an extra four hours a day for SEO, I would spend:
- 30 minutes - Commenting and interacting with influential bloggers and communities in my niche
- 30 minutes - Keyword/trend research
- 2 hours - Content creation around these trends and keywords
- 1 hour - Promoting that content and managing social media profiles. Even if your assistant isn't skilled is social media management, it shouldn't take too long to get him up to speed.
Content creation and promotion is the best and most sustainable way to earn links, if that's what your primarily concerned about.
Good luck!