A couple of things about the right angle drill attachment: definitely get the metal geared one. When you're working in a tight space, it's easy to bind up the drill bit, which will ruin the gears. Even with the metal gear set, I sheared the shear pin. Fortunately, the brand Avery sells is by a good manufacturer and they sent me extra shear pins for free. Very nice to work with.
One of the problems I had with the RA attachment is that it wants to spin instead of the bit. At first I used a vice grip as a handle for leverage but eventually I made a handle with a short piece of pipe and a hose clamp. If the bit binds up, the attachment will try to spin and you'll need more leverage than your hand can supply by gripping around the attachment.
Also, I ended up needing to make some cable runs through the fuselage that would involve holes drilled through the formers near the skins. There's a really long drill extension available (sold at Home Depot along with extension bits intended for running cable through a wall) that are fairly flexible. The extended bits are for wood, but the extensions are available for 3/16" and 1/4" shaft bits. The latter perfectly fit my unibit and allowed me to drill next to but parallel to the skins in several places. The extension is about a yard (sorry, it's at the shop so I don't have the actual dimensions or brand) and requires two people to use - one to guide the bit and the other to operate the drill motor. It changed the job from impossible to merely difficult. Well worth the $20 cost.
