Hello everyone,
Just wanted to wrap it up and post the final outcome, hoping that this will help future travelers in a similar situation.
I went for the Tourist Visa. I filled out the application online and, of course, was absolutely honest about every single question, including my last 87-day stay and my trip to Dominican Republic.
I went for the interview with a folder full of documents (Financial support letters, Bank letters to prove good balance, Spanish work contract, invitation letters from my host in US and from my filmmaking partner, long etc.). My whole approach was just telling the truth about me needing 6 months to both spend time there and finish my film and send it to festivals and other contacts. The interview lasted less than 5 minutes and the interviewer didn't ask to see a single document to prove my story. She asked me my marital status, who was paying for my trip, why I needed to go and what's my father's occupation, but again, she just believed me without checking any documents.
Finally, I was awarded a 10 year B1/B2 Tourist Visa, with a 6-month maximum stay per trip. My passport was mailed to me (with the new Visa) within two business days. Overall, very satisfied with the experience!
Thanks again to everyone who helped.