Here are my updated best guesses as to Idalia's peak lifetime maximum wind speed. I should add that this is also most likely to occur prior to crossing Florida, and possibly right into landfall.
Or looked at another way, I now give a 94% chance that Idalia becomes a hurricane, a 77% chance that Idalia becomes a Major, a 53% chance that Idalia becomes a high-end Major, and a 22% chance that Idalia becomes a Category 5.
There are still several things that could go wrong for Idalia and prevent it from becoming a Major hurricane, but there are also more things that seem to be setting up "right" (for higher-end hurricane).