The zen of body contacts

Okaayyy... I've been playing around with Some toy two-note-polyphonic key boards lately, (Hooray black blob chips!), and I've had some real fun with a no name Chinese number that resembles an early casio. The pitch resistor on this thing is really responsive, and I'm gonna replace it with a pot, but I also want a body contact for... no other reason than I want a body contact. Now I do know that larger body contacts can allow more responsiveness, but I'm wondering what I should use as a connection to best take advantage of this semi-solid copper demi-sphere I have that's a little smaller than a golf ball. I was thinking of welding a penny or two to it and soldering that directly to one of the pot pins, or maybe to the same lead that the pot will be soldered to.