So far as the "voltmeter pegging" there is no such thing as "unregulated output" from your alternator. All cars will measure a SLIGHTLY higher voltage at the alternator output post than they do at the battery, this is because there is resistance in the factory wiring. YOU WANT THIS AS LOW AS POSSIBLE. Higher readings can be caused by a number of things, mostly related to old wiring/ connectors and too-small wiring, and the ever present, ever troublesome, bulkhead/ firewall connector.

You must have a good regulator

You must have a good battery

You must have a VERY low resistance ground path all the way from the neg. batt. post to the frame/ body/ engine/ alternator/ regulator

you must have a VERY low resistance path from the battery pos/ feed/ wiring/ bulkhead/ ignition switch/ supply to the regulator.

Any of this wiring or connections will cause an overcharge condition.

So far as your voltmeter, all you've done wrong is hooked it up to cause a constant drain. If you park the vehicle long enough, it will eventually drain the battery.