100gb sounds like a good few downloads. I just downloaded a 15mb file to have a look at the video and I think they look and sound great.
Your competition/partners are going to want to know what's in it for them. They shouldn't just refuse you. So think about how they will benefit from promoting your product, and how your product will compliment what they're already selling. If you approach your competition with the 'what's in it for me' mindset I think you will get a better result.
I think it's definitely worth contacting potential parnters/competitors as you already seem to be getting positive feedback from the market and people are actually downloading your tutorials. That should help when talking and convincing them to promote your product.
You might find yourself bursting with ideas, I already have some buzzing around my head but just make sure you do something about it with those ideas. Dip your toes and test the waters.