I cut a muslin and they were good to alter as the pattern also has a 1 inch seam allowance to mess about with. As predicted the muslin was bloody massive. I will spare you a photo of what looked like clown trousers.
There are photos here because when I was looking/obsessing over trouser fit I found other people's photos a massive help to see the issues in real life - so here, I give you my butt pic, in case it helps someone else out with this pattern.
I started pinching in the waist and hips and also made the back seam curve a lot deeper to accommodate my derriere. I also took the front seam in slightly to mimic the flat-belly adjustment and it seemed to work. However as you can see they are not amazing........please excuse the jumper it was freezing, I realise it looks like cookie monster.
My main issue - despite the dreaded horizontal wrinkles at the front (of which I decided to do nothing about in order to save my own mental health) - was bagging under the bum. Not a good look. I then had a stroke of inspiration and decided to take the inseam in at the back piece but NOT the front.
It was at this point I realised I needed my life back and decided that this was to be my finished pattern. Woop. Next stop was drawing on the alterations with a sharpie then taking the muslin apart again to trace the 'new' pattern pieces.
Let the real fabric cutting commence!!