I would like to know how sensitive the tail is, and how sensitive in comparison to wings or torso? Also, what is a good way to clip a skiddish birds nails? I'm afraid of him scratching himself too hard.

The tail feathers don't have any nerve endings in them if thats what you mean. If you cut the very tips of the tails feathers he would not feel a thing. They would just get very annoyed with you as it would make flying harder.

You usually don't have to clip a birds nails unless its absolutely necessary (if they are growing so long then its a threat that they may pierce the birds skin) but if you feel like it is necessary to do so then all you need is some practice.
You hold the bird in your hand with its back against your palm. Its head should be between your pointer and middle finger while your other fingers hold its wings against its body. Never hold the bird so that you are constricting its chest as you could suffocate it. If you have its head controlled then all you need is to keep his feet still (you can get another person to help) and you clip the nails. Cut only the very ends off. A good way to tell how far is to imagine if the birds foot was standing on a flat surface, the end of the nail should meet the surface too. If you cut too far then it can start bleeding (sometimes you can see the blood vein and it can help). If it does, a sprinkle of white pepper can help to stop it. pets question and answers,www.5d2d.com

Hope I helped :)

Budgie Breeder