Ran this at a convention last weekend on tier 1-2. This was my second time GM'ing Dalsine, and as I missed every attack roll for Chalfon the first time I played him I was eager to see how it would go with a lower tier.
The party gave Chalfon plenty of time to prepare himself as they tried to negotiate with his illusion. After several rounds of trying to talk to him (I kept doing the evil guy laugh) the party's cheliaxian inquisitor took a swing at the illusion with his mace, and in comes Chalfon.
First round, I roll up 3 and 4 for his attack, missing the party's halfling rogue. Then their wizard casts Daze, Chalfon fails his will save. His AC 23 is too much though, and no one hits him. Next round he's dazed, and takes a few hits, still leaving him almost 20 hit points.
Another round of misses, and then two consecutive hits on the level 2 halfling rogue, who took 30+ points of damage from two hits and a shocking grasp and dropped instantly dead with his CON 10. Immediately after the party's elven ranger, played by the dead halfling's player's wife, scores a crit on Chalfon, dropping him and ending the combat there.
1/4 killed by Chalfon, which was also my first kill as a gm. Everyone had fun, though, and the halfing's player took it really well.
Wouldn't recommend running this for first or second time ever PFS players at a convention, though, as they will miss most of what's going on at the Dalsine manor and will end up quite confused by what they just witnessed.