I really wouldn't worry about galvanic potential. Aluminum needs hydroxide ion to make an electric cell. In a dry system, it's not much of a concern. If it was something to be concerned with, the quarters and dimes would be cooking off in our pockets, because copper and nickel have a difference in standard electrical potential of 0.5 volt. If you put a clad coin in water, it will corrode, but on your workbench there ain't much going on. Now when you bolt your aluminum heads on an iron block, that's different because the coolant is working as the electrolyte. Even so, it wasn't a big deal for the Big 3 auto makers, who mixed metals with impunity for decades. The 200,000 mile motors end up with some corrosion, but by the time they get there they're already spent and rotting in a junk yard, past their service life before galvanic corrosion became a problem.