Hola, PortAventura will most likely be busy during your stay as you will be going in the school holidays. The park will open at 10:00 and close at 24:00 so plenty of time to get on the rides and watch the shows. If your staying at one of the PortAventura hotels you can get the express premium gold for €51 and you get to keep the pass for the duration of your stay the pass includes 1 single front row on Shambhala, Furius baco and Dragon khan and unlimited access to the main attraction without joining the long queues plus reserved seating on some of the shows. You can still buy express passes if your not staying onsite but you will have to buy one for each visit.