Cricket - you may be right in the long run. I just worry about shuffling him around so much to try different things so I want it to be "right" the first time (my personality LOL)
Unless we are able to move, the ps is not an option at all. The one we are zoned for is in the bottom 10 in the whole state

If we do move, then we would consider the gifted cluster in the ps and try again next year after therapy and new tests.
Montessori already differentiates for him by giving him mostly 3rd grade lessons. The problem has been that he is so S L O W and it's a struggle to get him to complete enough of his lessons. He also can get very negative about school and mouthy with the teacher "this is too hard" "I don't want to do that right now" "that is going to take too long", etc. etc. Getting him to do homework at home has been a nightmare some days - like bringing me to tears awful. He says things like he will never be able to finish and he will have to stay in first grade forever. Or he hates himself (yes, that freaked the $&*! out of me). He is not that way all the time though and completes his own projects at home with no problem.
The Montessori did mention awhile back before we had the diagnoses that they would consider skipping 3rd grade and going to the upper el room (the rooms are 1st-3rd and 4th-6th) or letting him go to the upper el room for certain subjects, like math. So skipping 2nd for next year won't make much difference because he is in the same room. If the GT magnet doesn't work out and we don't move, I will definitely request a meeting this summer to hash out a better plan for him at the Montessori, now that we know more.
If we ever get into a position where homeschooling might work, that is what I would prefer for sure.