Thank you for your query and for taking such care in your contributions.
As you say, in most cases you will find one that is slightly better for some reason, particularlu when you look at the OCLC record in detail. If the only difference is pinyin word division then please go for the entry which follows the following rules:
- The first word of the title should also be capitalised
- Proper nouns, such as place names, are capitalised AND aggregated, e.g. 'Zhongguo' not 'zhong guo' (more complex cases are dealt with in the document linked to below)
- People's names are capitalised and separated into surname and given name, e.g. Mao Zedong or Du Fu
More information can be found here: http://www.loc.gov/catdir/cpso/romanization/chinese.pdf
I hope you find this helpful.
All the best,
Emma (Chinese curator)