I'm going to be running Doomsday Dawn soon, unfortunately my usual gaming group consists of only three players (not counting myself as the GM). I was originally just going to have my players build a fourth character that they would unanimously decided how he acted in combat, however once I read the rules for adjusting encounters I figured I would give that a try instead and avoid them having to control an extra PC. This is what I came up with.
A1.Slime Cistern: Trivial 1 1 weak Sewer Ooze: Creature 0
I gave the sewer ooze the weak adjustments from the bestiary.
A2.Mudchewer Central: High 1 3 Goblin Warriors: Creature 0
Removed one of the goblin warriors.
A3.Vermin Den: Severe 1 4 Giant Centipedes: Creature 0
Removed two of the giant centipedes.
A5.Fungus Bloom: High 1 Mindfog Fungus: Hazard 2
I didn't change this one, but this being a complex hazard with a level of 2 changes this from a low encounter to a high encounter for a party of 3.
A6.Purification Fountain: High 1 1 Elite Quasit: Creature 2
Removed one of the quasits and made the remaining one an elite.
A7.Goblin Headquarters: Extreme 1 1 Goblin Commando: Creature 1 1 Goblin Pyro: Creature 1 1 Goblin Warrior: Creature 1 Falling Rock Trap: Hazard 0
I removed two of the Goblin Warriors. I'm pretty sure this encounter has an error in it somewhere. It's listed as severe, but when you calculate the monsters it comes out to extreme. Either it was erroneously labeled as severe or there's one too many Goblins here (or I could be missing something entirely).
A8.Room of Ruined Repose: Severe 1 4 Skeleton Guards: Creature 0
Removed two of the skeleton guards.
A10.Befouled Shrine: High 1 Weak Drakus the Taker: Creature 2
I gave Drakus the weak adjustments. I also removed the giant rat, but according to James Jacobs the rat wasn't supposed to be there in the first place.
So this is what I got so far, if you have any feedback or ideas let me know. I think the Goblin Headquarters might still be too hard, and I might have made the Drakus encounter too easy.
One last concern I have is if by changing the encounters like this my groups playtest data won't be useful anymore. Will my group still be able to take the surveys and provide useful feedback with me making these changes? Should I just scrap all of this and go back to having my players control an extra PC?