I just received my packet of Bahrain culture but before I activated it
I went to Fisherman's Wharf and they had the San Francisco culture at
some trinket shop, called "Mr. Baker's Sourdough Starter" for a few
bucks, so I activated that one first.

75g white wheat flour, 25g rye, 200g water, 1g salt, 7.5g starter flakes.
I heated water to 35C, mixed with flour, and incubated at ~35C for the
first 3 hours, after which the temperature slowly dropped to the ~30-32C
the 25W oven light keeps it at.

I had googled Lactobacillus incubation and while the exact species in
sourdough are unknown, the optimal temperatures I glanced at seemed to
be around 37C, and one document even had a graph showing lactic acid
production peaking from 35-37C.

Tomorrow I will begin to slowly feed it the same proportions as above,
maybe every 4-6 hours, then increase it to twice a day for a week or two
before placing it in the refrigerator.

BTW, I want to activate my Bahrain culture, but I am worried that the
yeast and Lactobacillus from each one might contaminate the other. Does
this happen often and if so is it neutral in that one strain of bacteria
or yeast replaces the other and the symbiosis continues as usual, or is
it bad in that the new partner is harmful to the other, that the new
Lactobacillus might produce some waste product that is harmful to the
old yeast (or vice-versa) and kill the whole starter?