"Even a T-34 was supposed to have a bit of a hard time penetrating the armour. Yes, it could do it but not all the time."
The T-34 couldn't penertrate the King Tiger's frontal armour ever. The T-34 cannon wasn't even powerful compared to it's German counter-parts.
The King Tiger was designed for the Western front, because the designers knew the weight was going to be massive and the West road networks would hold it up. Whether or not the King Tiger saw more action on the West or East, I don't know. But I'll take Erich's word.