This paper describes the use of a unit selection corpus in carrying out an investigation of factors influencing specific aspects of the phonetic realization of tonal categories, concentrating on the alignment of peaks in H*L pitch accents in German. Three major linguistic parameters potentially influencing peak alignment are investigated. Two of them (syllable structure, nuclear pitch accents) are established influences while vowel quality is usually not considered relevant. Results from other studies are confirmed (peaks occur earlier in nuclear pitch accents, coda type influences peak position) and new findings are offered (in interaction onset type is more important than coda type). The presented procedure both describes the characteristics of the voice providing the corpus (allowing a more detailed phonetic realization of tonal categories, e.g., for speech synthesis) and offers general insights into which factors are relevant to the alignment of H*L peaks in German.