Dongfong Bubai mentioned that he was severely injured and would have died to the Seven Tigers of Ludong while talking to his lifelong friend Tong Baixiong.
He mentioned his training wasn't complete yet, but exactly how incomplete was it? Even before he practiced the Sunflower Manual, he should have been superior to Xiang Wentian. Even an incomplete Sunflower Manual would make him a super fast and stronger Xiang Wentian, and ultra formidable in his own right.
If we place a post-but-not-yet complete Sunflower Manual DFBB against a Great, I'd say they are on similar power levels. That means these Seven Tigers of Ludong might be superior to the Quanzehn 7 Masters!
Of course all this means nothing since it's pure guesswork off little detail, and could easily mean he didn't even complete his previous martial arts yet, but it's still fun to speculate .