water supply for weber carburetor

I just purchased a 32/36 Weber DFEV carburetor for my 1976 MGB. The manifold that was included has a pipe running through it and the directions indicate that for proper operation it must be connected to a hot water source. I'm sure there is a source for this connection, but if there is, I don't see a provision for it on my engine.
A second problem is that my 76 MGB has a manual choke and this carburetor has an electric choke. It occurs to me that if the current for the electric is 12 volts that I could add a switch to simply switch the choke on just as I would a manual cable and simply turn it off once the engine warmed up. I am in desperate need of some advice.

One of my questions about connecting the carburetor's water supply has been answered in the forums at the mgexperience.net forums. The original engine in my 76 B was replaced at some point by an earlier one. The original engine had a tap (or blanking plate for the tap if it was not in use) at the back of the head which is absent in mine. I am exploring other options for a water feed for the carburetor. Does anyone have an answer for me regarding the electric choke's voltage? If it is 12 volts, I think my solution would work. If it is variable from 12 volts, I could accomplish that function with a rheostat. Thoughts anyone?