Don't use exp calculations, they are completely bunk. Figuring out how to make a balanced encounter is all about bullshittng the numbers and lying to your players. So make what ever level fighters or what ever you want, and if we are mauling them, then there is nothing stopping you from giving them more hp or tweaking their stats mid fight.<br/><br/>This is especially true for bosses. Don't even do hp for bosses, just have them keep fighting until their minions die or one of the players does something epic to him. It makes for a more entertaining combat when the party barely wins the fight and stands victorious over their foes.<br/><br/>The general rule of thumb is to make the combat last between 5-10 rounds. Any less then that and it is just boring, any more then that and it is tedious and you'll piss people off.