Since Russell was asking about a rule of thumb for how tough to make encounters:
From the Savagepedia (Creative Commons Share-Alike license):
6.1 Challenge Ratings
For all of you who need some “math” to backup your encounter choices – Clint has proposed a “Damage Rating” system for checking out the lethality of your encounters:
Try getting a Damage Rating for your PC’s. Take half their Strength plus the bonus from their “standard” weapon. You can average this to figure out a Damage Rating for the group as a whole. Then compare the Damage Rating t their opponents Toughness.
- If it’s equal, then the PC’s have an edge over an equal number of opponents (where 2 Extras equal 1 Wild Card).
- If the Toughness is a point higher, then the fight should be about “even.”
- If the Toughness is 2 points higher, then it will be a (pardon the pun) tough fight (1 opponent for every 2 PC’s).
- If it’s 3 points higher, the PC’s are in trouble (1 Opponent for every 4 PC’s). And generally the progression continues to double.
So if your group has an average Damage Rating of 5 and you throw a 10 Toughness npc at them, then you should have about 16 PC’s or understand that it may take 4 PC’s four times as long to take him down. From Clint Black