dean, if you`ve never done it before and want it to look spot on, leave it to the pro`s it can be fiddly old stuff. there is a method which works great but you`ll need to google it.
the best jobs i did in my teens were when i took all the windows out to do it. i did my mates 205 and my ax with good results. you are allowed up to 30% on the fronts and rears don`t matter. personally i think light smoke all round looks best!
have a look on youtube for some how too`s if you really want to have a go mate!
