choosing the right alternator

I don't see why you can't eliminate that entire portion of the harness. I was thinking of doing the same thing. Most important though as mentioned, always run a new charging cable from your alternator to the battery (or sufficient battery connection point) Never run a higher than stock amp alternator through the ammeter
I am using a Volt guage and didn't hook up an amp guage. Car is now on the road and everything works great.