I know they have in the past, but I can't find it anywhere on their website but just to make sure: Does PortAventura offer Express Fast Passes? If they do still sell them, where can you buy them? And have they updated their selected ride list recently?
Seeing as any inversion to the GP is considered a loop and seeing how the chances are the mechanic was probably somewhat of a GP, he could've just meant "The tallest inversion" which IMO makes the Premier option in general a bit more likely.
^ Even though the height requirement is 42 inches for DarKastle, there's a sign outside the queue that says the ride may be too intense for young children.
*throws pie*
If it's Intamin, I'm afraid it's likely that it will have shoulder restraints. What was the last Intamin coaster to have lap bars?
Skyrush 2012?