In BD I only checked experience 10 levels below the opponent's level, and wouldn't expect the exponential relation to extrapolate far beyond the range of 3-10 levels lower. The problem with determining the function, is that it could be a single function, or several different functions depending on the level difference, with a cap that is set (more than X levels above and you get no experience) or built-in (the function itself goes to zero or negative values). Presumably if the function itself doesn't level off for much lower levels, there would be some kind of check that limits the experience you can get.
I would guess the default experience values are stored somewhere (maybe with the creature stats?) giving the experience when the character is at the same level, and that value is modified by the level difference function. You could search the data.000 file, or the game files in general, for the hex value of a late game opponent's experience (as large a value as possible will reduce the number of matches).
Teleporting Anywhere, via hex editorReviving dead NPCsThe starter tips topic was habit, listed with the differences between classes topic for anyone else reading this who may want to avoid minor spoilers.
Playing a warrior on normal difficulty I used Burning Wall (from a spellbook found in Mardaneus' house IIRC) for the spider at the bottom of the catacombs and the first heavy orc you run into south of Aleroth, but that was it. With my archer on hard, though, I didn't get much farther than I described in the topic Singo linked to before becoming busy and/or distracted. In general the game tends to get easier as it progresses, though.
There are various techniques you can use against strong opponents (some of which are as much exploits as Frost on a weapon or scorpion traps).
Share your monster killin' tricksChasing Josie... techniques for defeating Josephine
