[littlecranky67]

Your post is a good read for everyone trying to calculate number of RTT solely on the HTTP layer, which is done so often, but always wrong.

To add to your post, don't forget TCP congestion window scaling, which will add some more roundtrips - this mostly depends on the size and bandwidth of the ressources, so smaller sites like HN have an advantage here. Especially if the initial ressources fit within the initcwnd (10*MSS, usually around 15kb). But this, like many of the parameters you mentioned, are highly flow- and also software specific, it becomes so hard to make meaningfull predictions.