I've had less trouble taking on battles "over my pay grade" since choosing a rogue as my chief character and buying a "tank" fighter to do the main battling alongside Edér. But how I take on major battle groups is a method people may find tedious. Once my rogue is at at least 3 stealth (#1 requirement), equipped with a bow (#2), and has that temporary invisibility ability (#3, but I forget the precise name of it), I'm set. I park the party far from the anticipated enemy party and send my rogue ahead, scouting. As soon as one enemy (only one if possible) comes into sight, my rogue fires--then runs back to my group. If your party is far enough away, most or all of the pursuing enemies will turn back at some point, and the rogue can attack the last one visible and draw that one away from the pack. Sometimes my rogue finds a sweet spot where one step backward gets the target to retreat. Then the rogue follows, shoots (the target turns and chases), then the rogue retreats to the sweet spot, and repeats these steps until the target is dead. Or the whole party comes forward to pick off the loner. As I warned, it may seem tedious, but it's made my rogue the chief killer of the party and allows you to pick off one-by-one the members of a much stronger force. I'm sure you could do this with a purchased rogue, also, as long as those three criteria are met. Bonus if your rogue is high in Mechanics: you'll rarely meet a chest or locked door that rogue can't conquer.