I am trying to set goals for mobile web page load times using lab testing. The idea is to let users use a competitor's website and ask them how fast/slow the interaction is on a likert scale. As i'd be having actual page load times of each page the user visits I'd be able to understand what page load time is considered fast or slow or just about ok by the user. Then I would be in a state to set my own goals.

My questions are

1. Are there better alternative ways to set mobile web page load time goals based on user's input?
2. What should be the appropriate follow up questions for the above method?
3. Are there any loopholes you guys see in the above method?