Knockout Artist plus Sap Master

[Kain Darkwind]

Knockout artist allows you to use an unarmed strike to deal nonlethal sneak attack damage and gives you a +1 bonus on the damage roll per sneak attack die rolled.

Sap Master allows you to use a bludgeoning weapon to deal nonlethal sneak attack damage against an opponent denied Dex and allows you to roll sneak attack damage twice, totaling them.

Sap Master also has a prereq of Sap Adept, which allows you to use a bludgeoning weapon to deal nonlethal sneak attack damage and gives you a +2 bonus on damage per sneak attack die rolled.

Does this mean that a 20th level rogue with these three feats rolls 20d6+60 nonlethal damage on a sneak attack with his fist?

Or would we apply the Sap Adept and Knockout Artist bonuses to the base sneak attack, and have 20d6+30 nonlethal damage?

[Roaming Shadow]

The way it's worded, my interpretation is the second one (effectively 20d6+30). You're not actually doubling the total amount of dice rolled, you're rolling your die pool a second time and adding it to the first roll. A 20th level rogue is then technically only rolling 10 sneak attack dice; he's rolling those 10 twice, not rolling 20 die, meaning there are only 10 sneak attack dice to be counted for. I believe it's phrased that way for this very reason. Also note that Sap Master requires your opponent to be Flat-Footed, not just denied dex. While they are similar, "Flat-Footed" and "Denied Dex" are actually different things. It's a square/rectangle thing; you're denied dex when your flat footed, but being denied dex doesn't mean your flat-footed.

However, if you want to go crazy with the adding to sneak attack, get a ranged bludeoning weapon (like a throwing hammer or something), grab the Bludeoner feat, and use Sniper Goggles. Inside 30 ft, you're adding +2 per die feom Sap Adept and another +2 per die from Sniper Goggles, along with potentially rolling your sneak attack dice twice.