Bevelling the cane:
If you look end-on at the piece of shaped cane, you'll see that, at the end that will make the base of the reed, there is an acute angle formed between the surface made by the gouger blade and that made by the shaping knife. It is asking too much for this to sit nice and flat against the bit from the other end when the cane is folded over. So a bevel needs to be made along this sharp edge so that on the finished reed the edges of the two halves of the stock meet squarely. This can be done quickly with a Stanley knife or more slowly and carefully with wet and dry abrasive (start with course and finish with medium). The bevel can be carried through from the base of the stock up past the first wire on to the start of the blade, but the angle must become flatter as you move along the cane. The only way I know of to get this just how it should be is to form the reed encased in a rubber band or string, let it dry completely, open it up again and then bevel it by rubbing it against a sheet of sandpaper fixed to a flat surface and reform the reed in the usual way with 3 wires. 
Although I always bevel all my cane, many fine reed makers find it unnecessary. The advantages are an increased structural stability and greater air tightness. The disadvantages are a narrowing of the throat (this dimension probably being the most important part of a shape) and the fact that it takes time. Now is the time to check that the edges of what will become the blades are smooth. If necessary, lightly run some medium wet and dry along them.
The only brand of wet and dry I now use is Mirka (made in Finland). It is a real Rolls Royce of sandpapers in that it never cracks as you wrap it round your finger, it's no more expensive than other brandsand you can get it from various on-line suppliers.

Wire:
When the wires are in place on the finished reed, they should fit snugly against the cane and make contact uniformly all way round without needing to be pulled too tight. Brass wire is used by almost everyone. It needs to be 0.6 or 0.7 mm diameter. Many London bassoonists have bought a life's supply from the metal merchant Smiths of Clerkenwell. They only sell it by the kilo and you cannot ask to feel a bit before buying. Too soft is not good and too springy is useless. Springy wire can be softened by cooking it in the flame of a gas cooker for a few seconds, but it does go a rather funny colour and needs to be cleaned up afterwards with fine wire wool. The only wire I now use is from Rigotti (
http://pro.wanadoo.fr/rigotti/a_home.htm ). It is absolutely wonderful: malleable enough for the finest adjustments and just firm enough to hold its shape. Unfortunately it is only available on small reels and is not particularly cheap (well, it works out at about 4 pence per reed!). I pull a yard or two off the reel, give it a little stretch so that it's nice and straight and then cut it into lengths of about 3 inches so that it's ready to use. I'm sorry to say that most other brands of reed wire sold by suppliers are far too springy but can be used to train your climbing roses.

Go to Stage 5: Forming the Reed