It is true I would like him as on-par with public school as much as possible, since I don't know what tomorrow will bring per se. However I don't think this is going to be completely possible....he just isn't going to fit in to public school mode on every level. It is true he may have to go for a few years at some point....if he does, then we will have to deal with what he lacks then.
It sounds like you're in a good place now. As for worrying about public school equivalency just in case -- to be fair, not even 'worrying' but just 'keeping in mind' -- it can help to remember that MOST kids who are IN the public school system have tons of holes and delays too. Just because they've been in the system with particular curricular expectations doesn't mean that they're all meeting those expectations!
A few years ago I was looking over standardized test results and analysis for our province. I can't remember the exact numbers, but they were shocking enough that the precision doesn't matter, just the generality. Basically, a student was considered to be 'successful' on the test (I think this was for grade 3) if they achieved something like 60% on the test. A school was considered to be successful if like half of the kids had satisfactory results on the test. Some tests, provincewide, had like a 30-40% 'successful' rate, and this was considered to be acceptable!
So by absolutely no means does the curricular lesson plans mean an expectation of *mastery* at any particular grade level. In other words, if your child ends up having to go to public school for a couple years and is 'behind' or lacking in any particular area... he will NOT be the only one in the class! :)