Gone through the ones on top? Here's some additions for June!
(people visiting this thread in future years, 6-8 months before the exam)
Might want to replicate his vernacular subtleties:
https://www.youtube.com/channel/UC-x-90EoRqiEHMJFavFETPQThe only con that he has at times with his 口音(有啥问题?) would be to pronounce words more fully or not mumble so to speak (your going into a language exam, not a talk show unfortunately).
What I mean by mumble is when you compare the Baidu Translate voice to this:
https://www.youtube.com/watch?v=aC8CxfJHTLk (2:08-2:10) This idea extends from the Mainland vs Taiwanese accent video if you watched the 'Accents 101' videos. But here we're looking at the most minor of details or minuscule differences between Standard Mandarin and Colloquial Mandarin.