I didn't know you were supposed to remove the panel to replace these...

I replaced mine many years ago and used stainless sheet screws as well. Removing the rivets out leaves a of it portion inside the roof which will rattle around until it finds a spot to rest. I opted to drill the rivets out, I was confident I wouldn't go beyond it and damage the stainless. If you're worried about the bar, you can remove the gas strut and prop the door further open to make it easier/better angle to get to the rivets.