Is your camera neg? If so trim it out, it shouldn't be loads of work to hold the camera if it is properly trimmed. So if you feel like you are lugging a brick around then it probably needs trim. As for your buoyancy you should not have to kick alot to hover, when you do your safety stop use that as a time to work on some buoyancy, there is nothing else to do while you wait. Get to where if you are motionless you can hover. When you can do that with out thinking then adding a properly trimmed camera wont upset things much.
Thanks. Think I need to make the camera neutral buoyancy.