Look at your knee control first. My Singer 66 has a "button style" foot control box mounted in the cabinet that the knee controller pushes against. I've also seen knee controls that were a foot control with a folding lever attached to them.
I'm the opposite. I prefer a knee control. It's what I have on my Singer 66. My Rodney machine has a foot controller and it moves around everywhere, even on carpet. I'm seriously thinking about switching to a knee control on it.
Rodney