The new duration option is a great start!  I do have a couple thoughts:

1. Why is it limited to four options?  I’d love to offer ½ hour options from 1-4 hours, but that would require 7 slots…
2. I’m worried that people will easily overlook the current placement of the option and sign up for the default setting when they really wanted more time.  Could it be a right-hand selection before or after people select their start time? Or maybe just the option to select an end time?

Thanks for the work - really appreciate the added functionality!