Why would a protector make it more difficult to hit the hole?
- hole becomes smaller because of metal thickness
- raised metal deflects ball to post for rejection

If you consider the thickness of the metal as a ratio of the width of the hole I can‘t imagine it could be more than 1-2%. This number would be the increased number of rejections. Will we notice this?

If the metal deflects the ball in one direction this should work against you on one side of the hole, but in your favor on the other side - it should balance itself out.

So based on these points I would not think a protector would make much difference.

That being said I recently put Cliffys on my TAF and the chair scoop does somehow seem a tad more difficult. I find myself shooting for the swamp to start modes if the ball is on the left flipper.

Maybe there are other factors to the above I am not considering.

I switched out the JJP protectors for real Cliffy‘s on DI and I think they make it easier. I‘ve also reinstalled the real Cliffys a few times because the front was bending up. If I can slide a piece of paper under them, it‘s time for a reinstall. I have not played without a protector.