I'm trying to set the DC for something (poisoned caltrops spread wide across a street) which ranges from a mild annoyance (no poison) to truly dangerous (it is poisoned). I know the effect I want them to have in the game: The plan is to use these caltrops to slow the PCs down while also offering a small varied threat due to the poison. It's the numerical value that I'm having problems with; I don't know if a DC of 20 is too high or if it's just right. What number would be appropriate to get my desired effect?
I've done research into setting DCs for traps and caltrops, but none of these help me understand what impact a particular DC value will have on the fight.
What kind of perception checks are needed to search for traps? Is similar to my question but isn't quite accurate as while it is a trap, its not a trap (if that makes sense).
Spotting Caltrops. This was very incomplete and did not match what some of my expectations were, like there being only 25 in a 2 pound bag. I personally expected there to be closer to 50 (but this could be unrealistic as I've never held a real caltrop).
Detecting Caltrops While in Combat. Treating them as creatures of a Diminutive sized creature taking 10 on the stealth roll was a good idea, but there was much argument over various aspects.