Yes, Crusader, Quetzal and Gold are the easiest hybrids because the fails are so short. I've got Quetzal, Crusader and Angel on my Kindle account. I would always randomly try Diamond and Air going for a Gold. Yesterday decided to really focus on getting one. First was an Air fail, second was 44 hours! So now I'll have Gold on that account as well.
On my iPad account I've got two Diamonds, an Angel and a Quetzal. Still working on the Crusader and Gold. Then I'll worry about the others with longer fails times that I want (Anubis, Unicorn, black hybrids, etc)