If you need to alter the way references appear then you can pick another harvard based citation style, or if you can’t find one that is correct just use one that’s close and edit it in the citation style editor (google it).
It’s fairly easy code to learn and I’ve done exactly that to get my PhD references to be exactly how I want them… I’d share my harvard style sheet but it’s not 100% finished yet (still not got round to the minor stuff like maps and pers comm.)
Changing the number of authors that appear is very easy as thats just an option in the style sheet language.