I feel no need to install the string trees, seeing it all together.
When filing the nut, the v-shaped slots of the nut files were too wide at the bottom. So, second time round, I started the slots with the ‘correct’ file for the string, but finished the bottom of the slot with a file 2 sizes smaller, and a carving knife to finish the bottom of the high-E string slot. Using the nut files, meant the strings wobbled in their slot, so I started again with a new nut.