I read the suggested thread today and found some of the answers to my questions. I am still vague on questions 2 and 3. I didn't feel the thread answered question 4, but I will take the word of the thread that the low impedance capacitor was the correct one for high speed circuits. Could it be the best choice for something else such as circuit resistance through the loop of the battery motor and speedo? I think that is it.

Anyway, thanks to Jesse T for the insight. I thought you did an excellent job on the thread of digging into the issue.