for emperor, critical and master give about the same dmg increase. you can go with either one that comes up first, but critical is slightly more dmg in the endgame.
cull also gives 50% crit dmg so you send it on as many yellow skills possible however you can use chancellor when no SoE for best crit rate, but if you run my build with 1853+ swiftness you have 100% SoE uptime.
@syla4115 Damn. I didn't know you could reach that high swiftness, lol But the logic I follow is ditching Soe and go for a full yellow rotation and fully cast my US, as it beats out Rain with the Cull buff. I try to save my SoE for a smooth second rotation.