It may be conditioning as well. Don't know your experience level, but when post spawn reconditioning female bettas do not let them gorge. Just because
That is the only way to go. Remember your signature about buying the tank for the fish. You are doing it backwards and that is what makes it more complicated.
I fear you are all feeding the troll.
I think I may just do it the way I like. You can't be happy if you don't do it the way you like.
Just out of curiosity, would a single female fire mouth could have worked?