According to my tasks page [0], it took me 10 hours to carefully read the MDN CSS module on CSS building blocks while taking handwritten notes [1]. I started reading it back in December, and finished late February. Not exactly what I'd call an exciting read.
It took another 3.5 hours to transcribe those notes [2]. ~33% time overhead seems to be pretty constant for transcription I've noticed.
I'm still plugging away at Designing Data Intensive Applications by Martin Kleppman, also taking handwritten notes [3][4]. Currently 27 hours in and I've just hit the halfway point. It's a big book crammed with stuff.
0: https://pbat.ch/brain/tasks/
1: https://pbat.ch/brain/dz/ink/mdn_css1/
2: https://pbat.ch/brain/dz/mdn/css/1_css_building_blocks/
3: https://pbat.ch/brain/dz/ink/designing_data_intensive_applications/
4: https://pbat.ch/brain/dz/designing_data_intensive_applications/