You know those chip clips that techs use on computer chips to test /
troubleshoot the chips?

Why not do the same thing to PLL's before actually wiring the final
connections when expanding channels?

It would work, use alligator clips or wire wrap the wires around the pins
that match the designated pins on the PLL chip and then use some switches to
test the switching of channels.

Try it out.

Better than wiring the whole thing up and making the wrong connection.