Tom,
Were I you, and knowing what I know (which is more than most) about these switches, I would pick one with the same size connection studs as what you have. That stud size indicates the contact size and that is all you need to know. Besides, this way you won't have to mess with the cables at all.
I did boat work for a living for a long time. (I'm trying to stop.)
Most of these switches can be disassembled, cleaned and relubricated. You might try this before you replace it. Just be sure to open it carefully because there are springs in there that can escape with great velocity.
Matt