Keep in mind this is for an adult cat. So I want to build something nice and solid but I'm unsure of dimensions to use. For example... is 14 inches x 14 inches x 14 inches to small of an enclosure for sleeping? And if I put a 9 inches diameter hole and its 11 inches off the ground, is that acceptable to expect a cat to be able to jump through the hole to get inside or if I should have a step? Ugh... so confused and my OCD isn't helping.