It really is all a matter of personal preference. I tend to use the name most commonly found in records as you say, starting with the birth record. I also tend to use what makes sense. For example, my Swedish grandmother was born maj-britt...but from the time she came to America at 5 she was Maybrit so I go with the latter. On the other hand my Great Grandfather's name as Karl Oskar in Sweden for 25 years of his life and Charles Oscar for the last 10 years of his life in the US...I go with the Swedish version.