In a nutshell, hunters don't do anything different than any other ranged DPS for these fights.
With Rhyolith, you want to get those adds down but still keep enough focus handy if your wheelman asks for burst DPS on a particular leg. I've used SV and MM and don't see a big difference. I think I prefer MM because with SV I have an almost uncontrollable urge to drop frost traps. Snake traps are okay with SV but I feel that frost traps obscure the ground on that fight too much. Save your Rapid Fire for burst dps on a leg and/or when he's entirely a tank and spank.
Baleroc is a bit of a breather for DPS. The movement is minimal so MM hard-cast aimed shots are fine and SV sniper training comes into play plenty. Just don't get tunnel vision on your DPS rotation and miss your turn with taking the crystal. It's approximately a 5m50sec fight so you'll get to use Rapid Fire twice (or four times for MM).