I did 2 blocks daily. I spent an hour doing the questions and about 3 hours or so going over explanations and annotating in first aid (this got shorter as I progressed and didn't have to annotate as much).
Reading and annotating the answers is where you really pick up the knowledge. Carefully go through all the explanations, even the ones you get right. I only got through uworld once in my dedicated period (5 weeks, I did 10 blocks a week and did other review or practice tests on weekends). However, I think it was more helpful to do it slowly than to get through it multiple times. If the topic is high yield, you will see many questions on it, even with only one pass.