Dave........yer weird squarecan sparkie coil with mandatory "infamous ballast resistor" should pull about 3-amps (points closed); (6-or-12V) with points OPEN you will read NO AMPS. Ittza LAW, Kirchhoff's Law.
Yer 6-volt starter motor will pull about 150-AMPS.
Yer weaksister ignition switch will drop about 1.5-volts when turned on. INFINITY (digital overload) when turned OFF.
BIGGEST problem with 4-nipple dizzy is the points (0.015") Unlike the 5-nipple roundcan coil, the squarecan coil is somewhat "fragile". It overheats and short a few turns and suddenly, NO SPARKIES!!!
Ittza 2-bolt, 15-min job to remove the weird 4-nipple dizzy and change/adjust the points (0.015") on the kitchen table. Just un-snapple yer capple and letter dangle. Installation is a reversal of the removal ...except... finger start the 2-bolts and then install the rotor. Now twist the rotor so the OFFSET tang drive will mate with the OFFSET camshaft slot. Now tighten yer 2-bolts and re-snapple yer capple. Simple, eh?
Remember to "polish" the INVISIBLE corrosion from between the points (0.015") after installation. Me? I clamp a clean $1-bill between the points and pull. Iff'n yer really cheap, tear a strip from HEAVY brown paper grocery sack and use that.
As fer yer alternator, it should be intuitively obvious, yer engine MUST be running. It will put out as many amps as the 12V-battery requires to re-charge and generally that will be about 14.4-14.7 volts across the battery terminals. That is what the BUILT-IN solid state voltage regulator is supposed to do.
CAUTION: digital voltmeters do NOT like N-tractors 'cuz they have SPARKIES running around. Yer readout can be all over the place with the tractor running ........HTH, Dell, yer self-appointed sparkie-meister