[Althornin]

Note, i am stealing Since87's drawings

Examine figure 2:

We previously postulated that the value for Rbat would be roughly 1,000,000 ohms (thats through the electrolyte) and Rs is, as you say, also 1,000,000 ohms, then you have:
The current flow in the system will be:

2 Volts / (1,000,000 ohms + 1,000,00 ohms) = 1 microamp

The power dissipated in the system will be:

2 Volts * 1 microamp = 2 microwatts

Is this still going to be a problem? I guess. But it relies on the value for secondary paths to be 1,000,000 ohms, which im not sure of. Could be much higher, or lower.

Still:
Figure 3 represents a system that attempts to prevent the Galvanic corrosion using an external power source. By connecting an external power source so that the voltage differential across Rbat is zero, the Galvanic corrosion can be stopped.

BUT, the voltage applied by the external power source is applied across Rs. Therefore the current through Rs is:
2 Volts / 1,000,000 Ohms = 2 microamps

And, the power dissipated in Rs is:

2 Volts * 2 microamps = 4 microWatts
Which is hardly any current, so you should be able to do this.

Either way, wouldnt it simply be easier to add some of Swiftech's anti-corrosion additive, which BillA says will prtect even bare aluminum in a copper system?

FYI, with our HydrX™ inhibiter even BARE aluminum is protected

Note: Since87, i stole much of your pics and test, hope you dont mind (and i hope i did the circuit analysis correctly this time also)