There are a number of little things about Airhead ownership and repair that are sometimes hard to explain even if I know the answer. You have a number of good qualities that make helping you out so much easier. It's amazing the number of times riders with no prior mechanical experience come to these forums for advice and help but they need to have their hands held because they won't buy a manual. The inexperienced beginner mechanic thinks that real mechanics don't use manuals. Little do they know that we read them from cover to cover in our spare time and revel at the quality of a really good manual. They are the back bone of what a lot of us do. So I just wanted to say again you're on the right track
After the Clymers and Haynes manuals there is another that will prove very useful. It is the Bing
Carburettors Manual. Mine was published in 2001 and I understand there is a latter edition with some up dates. I think this is the next after the ones already mentioned. Find the Bing Web page and get the phone #. I think you have to call them to order anything. But here's the caveat, do not make a big order of a lot of parts from Bing. You will get their price list with the new manual (BTW it's pretty cheap at only 10 or 11 dollars I think.) And from there it is easy to compare with the prices from other sources. Not to start the discussion all over again but the fact is Bing parts are cheaper at the dealers than from Bing. But get the book.
Here is a link to one of the places that have after market tools for BMW. You may use them. There are others. They will sell you the adapters for the shorting the plugs method of balancing the carbs. You can also make your own, I'll give directions if needed later.
(not sure why the pic didn't work)