Cam plug with O-Ring

I made this plug today, haven't drilled the attaching holes yet. But I'm wondering if anyone else has tried this, and if it worked well?

I've never had a problem with the factory concave or pressed in plugs, but it seems an O-ring and fasteners would be more reliable. I've seen people use 'safety plates' over the concave plugs but I haven't seen the concave plug eliminated altogether.