Thank you so much for all the input. I think I've learned the knee control solution I need; it sure wasn't an easy answer to come by but I think it will do. It took...
1) Trial & error with opening up the power plug and trying but failing to connect both the foot control and power cord to the same plug.
QUESTION: the power cord is connected to metal clamp 1 & 3 and clamp 2 is missing, will that cause an issue if the center prong of the on-board terminal has nothing to plug into? If so, is there a source to purchase a single clamp as opposed to an entire plug casing?
2) Found a wiring diagram from
www.Sew-Classic.com where I also learned it requires two separate single-cord systems where the foot control connects to the back of the onboard terminal via ringed connectors but they are out-of-stock of the double-ended ringed cords, therefore I have connectors ordered to retrofit the existing cord.
3) Used Bakelite foot control cleaning instructions from
www.archaicarcane.com; I spent an afternoon to clean dust bunnies, corrosion, and carbon deposits from the foot controllers innards.
4) Will also use rewiring instructions from vssmb.blogspot.com to retrofit the foot control wiring to the back of the on-board terminal, and given these instructions are embedded within motor rewiring instructions, I'll likely be giving that a try as well.
Seriously, I learn something new with each purchased antique sewing machine; I have four machines now and three cabinets.