Lots of research and some trial and error of course
I think that you may want to start with just either the beCalmd or the OPC. BeCalmd was wonderful for me. Some do good with the OPC, but if you start both at once the problem with that is that you may end up wasting your money buying both products when in reality only one of the products is working.
What's good about concerta is that it's not affected by fatty foods. So he can go ahead and take the omega3 with his breakfast. What type of Omega 3 is he taking? Gel cap or liquid form? If he is taking the gel caps then he should take one with breakfast, one with lunch, and one with dinner. Make sure you buy it from a company that cleanses all of the possible toxins out of it. It should say on the bottle, if it doesnt you can just call and ask the company. It should be a mix of EPA and DHA.
If you start with the OPC I'm not quite sure on when the best time for that to be given is.
As far as the beCalmd, if you only give it at bedtime you will see no results. Or if you do that will surely be an amazing reaction!! BeCalmd works best when it's taken 3 times daily. 1 hour an a half before or after a meal would be sufficiant in most cases, unless the meal contains a lot of fats and proteins then 2 hours after would be better. So, about an hour in a half before breakfast, an hour after lunch, and then 2 hours after dinner is a pretty good schedule. Only problem is if he's in school during the times he needs the afternoon dose. How old is he? Is he in school all day? If he can't take an afternoon dose around lunch try giving it as soon as he gets home from school (but he'll have to wait an hour an a half before he can eat an afterschool snack if you do this)