Semi-related, I think the OP doesn’t give him/herself enough credit. Frankly, given then relative abundance of talent in China (1.4 billion population with general preference towards STEM subjects is no joke) and relatively cheap cost (you can hire a junior swe for probably $30-40k/year), there must be a reason the Chinese company decided to partner with you, an European living in a different time zone and speaking a different language. Take your vacation. Charge more. You probably have more leverage than you think.