[link=http://nimrifmodels.co.uk/setup.html]Base setup info[/link]
With the wrap to centre (wtc) I have heard you shove it in as far as it will go without the O-rings leaking!!! You should be looking for about 12,5" - 13,5" from the flange to the start of the convergent cone. If I remember correctly the Cooper comes in two types, one that will tune well on a wtc and one that won't....