So given that you begin an arrangment with an improvised dubbing, which songs would you say are the closest to being the same as the first original improvised version, and which have been most edited?
All have been heavily edited. When I lay down the original dub mixes I might record two hours of jamming and edit that down to the finished mix.
When editing 120 minutes down to 7:30 you can only afford to keep the very best bits and it can be quite heartbreaking having to leave out fantastic sections because there's no room for them.
That's why some tracks ['Jack's Cheese and Bread Snack', 'Mi-Loony-Um', 'From Trunch To Stromness'] end up topping 12 minutes.