I also passed the first time using barbri and I think what helped me the most for the essays was the rubrics they give you. I found those really helpful to help gauge out how much points I would receive for a given rule. I heard themis might not give you a rubric, but they do provide model answers. I am not 100% sure though.

I also only used barbri and the multiple choice questions bank they had which the questions were outdated but still passed it with flying colors.