The best way I found is duplicating all the needed parts, in other words, the only part I actually needed to modify. Don't duplicate everything at once, because you will probably duplicate sone unneeded stuff and eventually completely clog up your data editor with junk.
For example, duplicating the whole marine will duplicate it's ability in it's whole (making a stim pack 2 ability, a stimp pack 2 behaviour, a stim pack 2 button, a stim pack 2 model, a stim pack 2 actor and so on...), which I wanted to remove because I didn't needed stim pack in my map.
One last thing you need to remember is that 2 units can't share the same actor, even tho you don't modify it. In all basic unit duplication, consider duplicating the unit and the unit actor (which contains the model) at last.
@DrSuperEvil: Go
The second one. one actor can not refer to multiple units. I have no idea why, but I'm pretty sure there is a good reason for it.
@RaGeOrRiSe: Go
The best way I found is duplicating all the needed parts, in other words, the only part I actually needed to modify. Don't duplicate everything at once, because you will probably duplicate sone unneeded stuff and eventually completely clog up your data editor with junk.
For example, duplicating the whole marine will duplicate it's ability in it's whole (making a stim pack 2 ability, a stimp pack 2 behaviour, a stim pack 2 button, a stim pack 2 model, a stim pack 2 actor and so on...), which I wanted to remove because I didn't needed stim pack in my map.
One last thing you need to remember is that 2 units can't share the same actor, even tho you don't modify it. In all basic unit duplication, consider duplicating the unit and the unit actor (which contains the model) at last.