The setting for Aurora is here:
https://www.stackandtile.com/sat/starsaurora.png
As far as I've heard, Pokerstars.ES forces you to use Aurora, and that option isn't even available. So if both .EU and .ES are both using Aurora, just make sure both skins are using the same Mercury theme, so SAT isn't confused. You don't want to use Other and have two separate Stars sites. You either want both skins to both use Aurora, or both not use Aurora
As for the "Check" hotkey.. SAT's fold/call/bet hotkeys correspond to the 1st/2nd/3rd buttons on the table. On most sites, the Check button is the 2nd button, so you would use SAT's "Call" hotkey for it. However, when possible, the "Fold" hotkey will also click Check if you can check for free on most sites
https://www.stackandtile.com/sat/starsaurora.png
As far as I've heard, Pokerstars.ES forces you to use Aurora, and that option isn't even available. So if both .EU and .ES are both using Aurora, just make sure both skins are using the same Mercury theme, so SAT isn't confused. You don't want to use Other and have two separate Stars sites. You either want both skins to both use Aurora, or both not use Aurora
As for the "Check" hotkey.. SAT's fold/call/bet hotkeys correspond to the 1st/2nd/3rd buttons on the table. On most sites, the Check button is the 2nd button, so you would use SAT's "Call" hotkey for it. However, when possible, the "Fold" hotkey will also click Check if you can check for free on most sites