Thanks! Great tip on the cord- I'm going to have to open that back up and take a look.
I really dig those adapters you made too.
Now, would I have any problems if I use a 10/3 commercial extension cord with my pigtail? How will I know what side is neutral in a plug I can't open up? Or should I cut the ends off and install my own receptacle and plug so I know they match down the line?

Sorry if that's an ignorant question. I'm not sure how to test for neutral with a meter.