During the 1800's there was a territorial war between the different missionary socieites in the UK. The solution
was to divide up the British Empire among the competing
denominations. This division was also expanded into
missionary territories outside the Empire.
Rhodesia/Zimbabwe, along with Korea, was given to the
Church of Scotland/Presbyterian.
This not only explains the SCD connection in modern
Rhodesia but also the number of Presbyterian Churches
in Souther California with Korean languages services.
A further result of this is the UK universities of choice
for university students from former colonies -
Students from "Presby" colonies usually go to
Scottish universities, "Pisky" colonies to
Sudan was given to Catholics
Hawaii was given to Methodists -
Dole [as in pineapples} was a Methodist missionary
Argentina, Hong Kong, South Africa - C of E
Quakers were not a part of this division but were a
strong influence in the Gold Coast/Ghana. While there
they "felt moved to" develop some industry so that their
converts could participate in world trade. There solution
was the production of cacao beans for chocolate.
Cadbury and Roundtree were Quaker missionary families who,
like the Doles, did well by doing good.
This pattern did not hold true in areas where British natives took over from the indigenous:
USA, Canada, Australia, Tierra del Fuego.
Here the religious and SCD patterns follow those of the
UK regions of origin.
SCD is strong in areas where there was a large Presby
I don't think the Welsh/Methodists in Tierra del Fuego have much of an SCD tradition.
There is a song, music, dance tradition in Appalachia
(not an area with a strong "Pisky" presence),
that has well documented connections with Scotland.