I managed to get http://usdlc.net ready and live on time, but first load was horrendously slow. When deciding on a JavaScript deployment approach, I believed the pundits who said that more parallel connections were better. It was fine locally and acceptable on fiber, but ADSL or 3G was nightmarish slow.
I minimised connections by combining all into one CSS and two script files – one at start and one after load for all later functions.
I then created static gzip versions of these files – reducing 700 script files to 160k.
Lastly I kept connections opened for static files to reduce reconnection overheads.
http://usdlc.net is an application – so it will always have more overheads than a web site. But now it is acceptable – even on less than optimal connections.