Sibes aren't that prone to bloat, if you think about the working sled dogs that do the long distance races, they tend to eat and exercise without much of a break in between. However, I always rest my dog for at least an hour after feeding, I feed in groups and they stay in their pens for that hour after they've eaten so that they get total rest.
My GSD/sibe cross girl Nannuq bloated earlier this year, and if I hadn't known the signs (thanks to a friend who has Great Danes and lost a dog to bloat) she would have died. I got her to the vets very quickly on a Friday night, about 10pm. They tried passing a tube to relieve the pressure, it wouldn't go, so she had to have an operation, finally all finished at 3am. She has since bloated again, but she didn't torsion this time, mainly because when they operated on her previously, they stitched her stomach to the wall of her abdomen. So yes, I am paranoid about bloat, I know too many people who have lost dogs, even breeds that aren't prone to it, to take any chances now.