I think it is futile to expect anyone to come up with a perfect set of standards to say if it's a good idea to carry a gun or not. Why not just pick a few drills that seem reasonably representative of what you need to do with your CCW (most likely not 10 rounds at 25 yards, although I don't think that's a bad thing to work on), and then shoot both with your red dot gun and your ironsighted gun, and carry whichever one you do better with?
Also you don't really need live fire to figure out the trigger mechanics of the LEM, do you? Why not just work on that in dry fire and see what happens?
Also I don't like measuring progress with B8 scoring rings. A 96 on a B8 could be eight 10s, and two 8s, or it could be six 10s and four 9s. The first one would indicate a much lower level of consistency than the second one, but the numbers don't capture the difference very well.