Ideally I should adjust the URL hierarchy so that it

Ideally I should adjust the URL hierarchy so that it is more simplified for a site that I am working on. My question is what hierarchy is the better format to follow?

http://forwardprogressclass.com/classes
http://forwardprogressclass.com/classes/arc-1
http://forwardprogressclass.com/classes/arc-1/register
http://forwardprogressclass.com/classes/arc-1/register/payment
http://forwardprogressclass.com/classes/arc-1/register/payment/thank-you

or is this better?

http://forwardprogressclass.com/classes
http://forwardprogressclass.com/classes/arc-1
http://forwardprogressclass.com/classes/arc-1/register
http://forwardprogressclass.com/classes/arc-1/payment
http://forwardprogressclass.com/classes/arc-1/thank-you

Any guidance or input you could provide would be most helpful.

Thank you,

Jeremy