I've been to China a few times, and the last time I applied for a visa (two years ago), there was no option for duration. You just give them (the Chinese visa service in London) your credit card details and hope for the best. I ended up getting a multiple-entry, two-year visa, which was great but really expensive. Travelling to China is already expensive, such that it's unlikely that I'll go more than once in a two year period (I wasn't able with this last visa, for example).
Has the process changed in the meantime, or is there some other way to get a short duration, single entry visa? For example, last time I did it all online and by post; would going to the application centre in person make a difference? I realise Shanghai, Beijing and some other cities have 3-4 day transit options, but that’s not really long enough.
EDIT If it makes a difference, I have Chinese in-laws.