This is what I'm sure will be the first of many Rubies in my future!
I measured between a size 8 and 10 and cut the 10 to make sure there was enough ease around the arms. There certainly is - next time I will go with the 8. I didnt make any adjustments to the pattern other than to add 10cm to the length.
I picked up the printed silk scarf for $5 in a clearance sale recently and knew straight away that I wanted to make a top or dress. The black fabric is a rayon with some stretch on the cross-grain (a remnant also on sale!), which I've never worked with. Both fabrics were lovely to sew up and delightful to wear.