I actually got gems (3) out of my parade today & a Bo Peep hat, woohoo! My ravens are still every 3 hours and I'm over the 290.
Lucky. I spent over 3,000 magic on a parade sending the Monsters Inc, Tangled, and Wall-E floats with a chance of receiving up to 15 gems, and I got none. I got just over 1,000 magic back.