Comment by crawshaw

If you want to have fun with this: the initial window (IW) is determined by the sender. So you can configure your server to the right number of packets for your website. It would look something like:

    ip route change default via <gw> dev <if> initcwnd 20 initrwnd 20

A web search suggests CDNs are now at 30 packets for the initial window, so you get 45kb there.