making sense of dash cluster connector measurements

What I would do is post a good clear photo of the front and rear of the cluster on here. That will give you what amounts to a "diagram" of the cluster.

Also, doesn't the manual show the function of the wires at the connector, regardless of color?

You can figure out what some of them are from this by tracing them back

http://www.mymopar.com/downloads/1964/64DartA.jpg

http://www.mymopar.com/downloads/1964/64DartB.jpg

connector.jpg

Tan, Light Green are the dash turn signal indicators

Gray is oil pressure light/ sender

Dark blue is "ignition run" and is likely what is powering the gauge IVR which might be inside the fuel gauge.......See if yours has 3 terminals

Red is high beam indicator

Orange is ALWAYS dash dimmer controlled lighting

Violet is temp sender

Black I THINK is "accessory power"

Light blue is fuel tank sender