MoutonRustique
Explorer
This is extremely efficient in terms of ease of use.I've had success with just replacing the monster's save with its ability score. For example, if a monster would normally make a Strength save, the PC's roll with bonuses must beat the monster's Strength score. It's certainly not perfectly spot on. But it works very well for a fast and dirty system.
I also use a monster's ability score for contested rolls too, just to cut down on the amount of rolling.