What is worth screening for with scanner?

[Boozie]

I more or less just don't want to be totally screwed. I know on normal it's possible to make any game work, I just don't want to overcome pointless challenges because X spell wasn't around in the game.

This will most likely be my only playthrough. Not to knock the game, I just have a ridiculous backlog of games I've bought on steam sales (this and TL, which I beat, were one of them) that I'd like to make headway on.

So far, I ran with my original game, no trap on the first three islands or at least not yet unlocked. Shouldn't be much of an issue.

On another note, after coming back to the first island with 5x the leadership is it even worth fighting the "weak" stacks? I get crap xp and feel like I should just leave them there for sacrifice boosting or when I get artifacts that need 50battles.