I would have then split my tactical squads into combat squads, ditched the missile launcher and put two cardboard coffins to transport them, or maybe even Razorbacks if you could afford it and then have the other two combat squads running behind the Rhinos using them as cover as they advance. I cant remember if SM's have krak grenades as standard, if they dont, then take them as your predators cant be relied on to take down the Russes that will make a mess of your marines.