I am VC. I invest in hard tech. That said, opinions are my own.
Unless you come in with a strong background reputation or intro from the top 1% of our network, I would probably not read a document that takes 30min. I cannot imagine many people would without enough incentive.
Think about it this way, if you're going to commit to watching a movie, do you do research beforehand to choose? The common joke is you spend more time searching for recommendations than just watching. The psychology is we want to de-risk committing our energy/attention. This similarly applies to founders sending technical tracts. We do eventually read a tremendous amount of technical details (lit reviews, white papers, etc...) but only after we have understood that the opportunity is worth the effort.
Okay, all that said, there is a deeper code smell here. I think you are likely mixing product implementation with market opportunity. Description of the implementation of your product takes lots of time and explanation as you state above. BUT, you should not be doing that in your first pitch. The first meeting should be explanation of the market opportunity. You aren't selling your product. You are selling your market. If I'm sold on the market, I want to hear why your product captures it afterwards, not before.