I have a drobo, so the disk gets larger as I need it to. I'd like to put a encrypted sparse image on it, and they grow up to the size you set them to be. Currently my drobo is 8tb, but I don't want to create a system with an expiration date. Could I make, say, a 500tb sparse image on it? Sparse images grow up to the size of what you put on them, up to the premade cap. Thoughts?