I've done the Alhambra in the morning and I say the earlier the better. They only allow a certain number of people in the palace at a certain time, so if they hit that number you spend a lot of time standing around outside. And if it's raining, as it was when I was there...well it's not fun. It gets busier as the day goes on. By the time we left, there was a traffic jam of buses all the way down the hill that leads up to the alhambra. And it also seemed to get a bit crazier as the day wore on -- more people = more chaos. But, since you are staying at the Parador (where all you have to do is walk out of the hotel), I think you'd be fine to do the 10 am tour. Our tour was split in two -- I can't remember what the dividing line was, but we definitely took a break and went into a little gift shop that had some food and drink. By food and drink I mean cheetos or crackers and a coffee machine. So, not a filling meal by any means. That said, I've heard the Alhambra at night is fabulous -- not dusk but night. There is a restaurant, the of which I've forgotten of course, that sits on a hill across from the Alhambra and you can eat dinner with a fabulous view. Definitely worth it. If I can find the name, I'll post it.