I have a 2007 Shadow Spirit C2. Last year, I looked into what I needed to install a jet kit and get it running right once I did that, and I selected these two items from Amazon:
a flex-shaft carb adjuster screwdriver, and
a Motion Pro D-shaped Socket Bit (90 Degree 1/4" Hex). I remember comparing the socket to the Honda tool in one of the manuals I have, and it seemed like it would work.
BUT, as you might guess from that last sentence, there's one big caveat to this: I have never actually used these yet! So I am not positive they will work properly.
Also, your carb may have a welch plug where the air screw is located. Mine does, and that's the biggest reason why I haven't installed the jet kit--my bike runs fine for the most part, so I don't really want to risk grenading the carb body by making a mistake while drilling the welch plug out.