I use a 10g tank full to the top with water to spawn in, water temp 80F, heavy planted, both rooted and floating, I use either water lettuce or a sword plant leaf for the nest.
I have the planned breeders in separate container so they can't see each other while conditioning for at least 2 weeks, they are feed my homemade food, mosquito larva, guppy fry, chopped red worms.
I place both Bettas in the spawning tank at the same time and I will have spawning within 2 hours to 3 days.
As long as I have plenty of plants for the female to get away from the male to rest and hide, I will have very little if any damage to her.
I remove the female once she leaves the nest area after spawning
I remove the male once the fry are free swimming
I use pond, ramshorn, trumpet snail, plants and aged tank to help produce infusoria for first fry food
I start doing daily 50% water changes once I start adding live food to the tank, usually about 2-3 days after the fry are free swimming
I place plastic veggie wrap over the top of the tank usually right after I remove the male but at least by week 2-3 before their labyrinth organ starts to develop, it is important to have the air above the water warm and humid for their first breath to prevent swim bladder problems
As the fry grow I will start to separate them to other tanks for grow-out keeping the big ones together, smaller ones together etc....I use tanks from 10g to 75g for grow out.
Lots of different ways to spawn this species.........it is finding what works best for you and your set-up and breeders....good luck...