To date, 9 of the startups I have worked with have entered due diligence with VC teams, and 5 have successfully raised a combined $69M in series A funding.
I've found this above narrative arc to be the most effective at convincing a VC team to take your story seriously. If you provide a good outline, Series A decks typically take around 3 weeks to design. Its been my experience that you shouldn't need more than 25 slides to get through a compelling Series A pitch (this includes appendix slides).