Hi, I have no experience of combo classes and to me they look like a good solution on paper. When you say that you took the Principal's recommendation last year was this for a combo class? If so and it hasn't worked for you, you could explain why it hasn't worked and ask how things can be improved. You could also ask if it is possible to meet the proposed teacher and ask what sort of experience he has and how he will accommodate your DS's needs.
Don't feel under pressure to make any decisions, just say that you and your DH need to discuss everything and schedule to meet again in a week or so.
Sorry I can't be more help, but I don't have any experience of combo classes.
Good luck and try not to worry.
