two given names are quite unusual at this period (in later period Manx would use the middle name much to confusion of indexers) - the use of David in the Christian Clan is also fairly unusual - however as you have discovered Christian is close to being the 'Smith' of England - very common. The other factor that you might need to consider is that the Manx knew illegitimates by their father's name (see
www.manxnotebook.com/famhist/genealgy/illegit.htm )
The IGI has no obvious match tho a couple of Daniels in Andreas - so where did your Andreas info come from ? do you have a burial, census record etc ?
ETA - there are two wills summarised on my manxnotebook for Ann Christian + Joney Christian both of Ballachury (1st Jurby, 2nd Andreas) that mention Davids in abt correct time frame - Ann is widow of David Christian and she mentions sons daniel and david tho not sure abt bapt of David but David appears to be common in this family and in the right part of Island - there is a 1785 will of David (bur Jurby 17850106) but I haven't seen it (David m an Ann Christian Andreas 17740409 in reg noted as dc jurby;ac otp[of this parish ie Andreas]
