Fresh tomatoes are definitely better, but you need to be careful not to make your chili too acidic. I'd say par boil your tomatoes, peel the skin, cook you meat and tomatoes for at least three hoursand let it sit overnight in fridge. You can get inspiration from the International Chili Cook-off site. They post winning recipes. https://www.chilicookoff.com/winning-recipes. If you want to win, I would consider the audience/judges. Cook for them, not the best chili. For example, I work in a department with a lot of Vegans and we had a chili cook-off. Guess what type of chili won? If you said Vegan chili, you are correct. If your audience is a bunch of midwesterners, don't make it very spicy.