I would keep it positive and simple.

List a few behaviors and what you find useful. Maybe list a few things that he is great at:

Little johnny is great at washing his own hands and putting his coat on. He can struggle with X and I have found it useful to ____. When he is having trouble staying focused (for example, getting dressed to go outside) he responds well to ___.

If you tried some things that didn't work you can mention it. Johnny really responds to my ____, I discovered this after first trying ___ and ____.

Just keep it factual and simple.

I don't think I would go into detail about the things that he is still struggling with that you haven't been able to work through and i wouldn't get into detail about reasons why you think he is acting up etc (unless it is behavior before meals and nap - I wouldn't lay blame on the divorce or parents etc).