1, you tractor came with an ammeter.. not a voltmeter. I'd need to know which you have in order to tell you what to wire up.. they wire up different.
spade plug #2 should be jumpered to the charge lug.
spade plug #1 is generally ran thru a lamp like a 194/marker lamp, to the same side of the key switch as the coil.
also.. is this using a 12v coil? or a 6v coil and a resistor? or just the old 6v coil left their cooking?
In any case.. i reccomend a napa ic14sb 12v coil and no resistor. if it already has an equivalent... you are good to go.
if it has an ammeter, and it is a 2 post styel vs loop style, it's simple.. wire alternator charge stud to one side of ammeter, wire from that same side feeding key switch... wire from that same side feeding lamps.. other side of ammeter hits hot side of start solenoid.
if a loop meter.. it may not even work.. but you run a wire thru the loop.. wire same way yhr 6v diagram shows.. think of the wire from the alt charge stud as the wire from the old vreg bat tab.
if it's a volt meter, one side is negative, thus ground.. the other side hits the switched side of the key switch.. same as coil, and same as the one feeding the lamp and #1 on the alternator..