Temperature sending unit

[Nico73]

Hi Gentleman,
the waterpumps of my 1936er 21 Stud Flathead have cast bosses for sending units. Do you know, if the sending bulbs for the cylinder heads fit's on them?
( Part Nr. 8A-10884 & 990 at Mac's )

Would you mount 2 for each cylinder-bank?

And do you have any pictures of the old 6V temperature-Gauges?

Thanks a lot, Nico