I think you mean the same thing on force carbonation and carbonation by CO2. Technically bottle conditioning is still carbonating by CO2.
Kegging is simple once you figure out the parameters involved. Unless you get elaborate with individual regulators you are most likely going to have a single pressure to your tap lines. This pressure will result in a force carbonation in your keg. At varying temperatures (colder absorbs more) you get more CO2 dissolved into the beer which results in a more lively carbonation. My reference charts online all seem to be dead, many books have reference charts on styles. You'll want to seek out the CO2 recommendations for an Irish Stout at the recommended serving temperature (or whatever temp you are keeping the beer at).
Some people will say roll the keg, I prefer to wait and let it happen. Usually it takes about 3-4 days depending on pressures, temps, etc. Once that happens you have beer with the appropriate level of carbonation.
The next trick is making sure that beer comes out of the tap properly. In order to preserve the beer and get a great pour you will need to balance your lines. Every material has a different resistance it adds to flowing beer. Too much resistance and your beer will pour very slow, too little and it will fly out causing massive foaming. I think this is the real key and if you will run multiple taps from a single pressure you have to work this into the equation. I'm not real experienced on dealing with that issue so hopefully someone else can chime in.