Hola Michael,
I am venezuelan, i am an engineer but also a language teacher. I worked formally as a french teacher for 4 1/2 years (before coming to France) and often as an english teacher, so i think i could help you get your grammar right while practicing your prononciation and learning more vocabulary.
I am currently living in France for studies, so while the time difference is reduced (compared to China-LatAm time difference), i would only be available thursdays and weekends during the time window you gave. From previous experience, I would recommend to practice for 4 hours a week at least.
If this works for you, please contact me for any questions!
Que tengas un buen día,
Isabel