Tong (1862) uses Chinese characters which when pronounced allow no consonant clusters. Conversely, English sources appear to represent consonant clusters, but sometimes show epenthesis as in sitop. The only available phonetic transcriptions are by Hall (1944) who comments:
"Chinese speakers simplify certain clusters." (page 96) However, Hall lists a number of two-consonant onset clusters in material dictated by his American informant. It is likely that European speakers used more clusters than Chinese speakers.
Source: Tong 1862: VI.2
Source: Dier 1860: 301