80's Fuel Gauge Sender Wire Size/Color

For a project I am working on, I got hold of a fuel tank from an 82 diesel blazer, and am wondering what gauge wire I should use to splice to the sending unit?

I'm assuming the size would affect resistance, and therefore gauge readings? Looks like it's 16 or 18 gauge?

Also, the sender has 3 wires coming out of it - is the largest one for the gauge?

They all appear to be white.

Thanks in advance.

Joe.

The resistance of the wire is insignificant compared to the resistance of the sender. Either 16 or 18 will be fine. 20 would work, but isn't that strong mechanically.

Anyone know if the sending unit needs to have a ground wire in addition to the gauge sender wire?

I was guessing the tank itself provided the ground?

I ask because my Blazer tank sending unit has 3 wires coming out - I was thinking the other 2 were for the water in fuel sensor (1982, older WIF setup)?

Or is one for a ground, one for WIF, and the other for the fuel gauge?

Thanks.

Joe.