DS1 (16y) is adhd, and he is now quite a nice chappy to be with (apart from teenagedom!) His worst peak of ADHDness was around 8/9yrs it plateau'd for a few years and it isnt too bad now - still very impulsive, but 'better'.
Hmm as for tips... i think the '1 instruction' as you've noticed is a must. The things i read in your OP seemed to be about right, I think the only thing i can add is: be kind to yourself, and remember that his actions are NOT personal, hes not doing it to be difficult, its just that his brain is going far too fast for the rest of him. Quite honestly being ADHD must be exhausting! His brain has to send out at least double the messages to get the job done because of all the messages that go astray! Hmm what else? invest in some DVD's for his room to give everyone a break! handheld games machines are also brill because all the action is still going on, but they can do it 'in one place' ie going to the doc's or dentists, or a long car drive.
I found that plain sugar does give him a bit of a rush, but its the additives (avoid aspartame!) and colourants that do the damage - so some blackcurrant squash is worse than candyfloss!
Rollerblades are good, they take up a lot of energy when learning!!! trampolines (even the diddy ones) also have their uses.
DS1 is still quite 'young', only last week he was riding on the bottom of a shopping trolley, but it kept him amused so what the hoo! hide and seek in the clothes racks is also a fave game. We have a family friend who undoubtedly has it too, but he has a wife who loves him, and 2 children that he cares for (in his own way), he still has teenage obsesions for R/C cars at the age of 32y, so im not expecting DS1 to grow up anytime soon!
sorry to ramble - probably havent helped at all ...