Charging issues with Toyota style Denso Alternator

Anything more than 12.8V (voltage of a 100% charged battery) under all the loads is just fine, since this isn't a police car or something where it will idle all day.. I'd say your problem is solved.

Another question would be what gauge wire goes from the stud on the alternator on it's path to the battery? It should probably be 6 ga for that high output of an alternator but you might be able to get by with 8. If it's 10 or smaller the wire will almost certainly be causing a voltage drop.