I think an experimental setup is available. Rent a seaworthy vessel and travel out to an empty stretch of the ocean, not on shipping lanes, so there is no other conscious being from horizon to horizon. Hold a deadman switch, which is wired to a shotgun which is pointed at a watermelon, after you have injected yourself with a powerful sedative.
In the normal view of objective reality, when you are unconscious from the drug, your hand will relax its grip, the switch will close, the gun will fire (let's say after ten seconds, due to a delay timer), and the watermelon will be blasted. You will wake up later, with the wounded watermelon already having happened.
Now, if consciousness is required for things to exist, then the whole experimental setup will disappear while you are unconscious and will not reappear (and you will not notice your grip on the dm switch has relaxed) until you start to awaken. After ten seconds, when you are fairly awake, the gun will discharge and watermelon goop rain down upon the sea. And you will witness this event.
This experiment should determine which theory of reality to go with, pretty decisively. (if you're really confident about the consc=existence theory, of course, you could just point the shotgun at the bottom of the boat, fully expecting to awaken and switch off the timer before the gun fires)