Neither of you answered the question, nor was the answer on any of those pages. He wasn't asking about how they effect QD, he was asking about how they boost Courser's Roll.
The answer is, no one knows. Courser's Roll was never tested, so how the boost boost it is unknown.
Doesn't mean someone in the COR guide thread hasn't tested and not posted results. If I could answer him I would have, I directed him to a place where he has a chance to find an answer.
Exact snapshot values are quite difficult to determine; even static snapshot gear values tend to be unknown. I'd be very surprised if anyone had an accurate answer to this question.
If SE cared to at least put the exact snapshot on gear it'd be easier to test cause we could start from there to make comparisons. As it is testing snapshot is a pain particularly due to rapid shot which reduces delay by random amounts.
As for the boots they add a small % of delay reduction, just like all rolls gear simply increases the potency. How much? Nobody knows.