The flight plans are installed onto the server(s) by the Server Admin (DD26) and users don't have the ability to add their own directly. Years ago some people used to create new flight plans and submit them to Dave and he would change out some of the servers on a monthly basis (i.e. on the first on the month a new flight plan would appear). Longer hop lists, like the Round the World server, never changed so that people could continue with the hop list over extended periods. I was one of just a few people who actually completed the 950+ hops and it literally took me YEARS to finish the list!
As far as I remember the speed is only displayed in knots regardless of altitude and is not changeable. I also don't remember anymore if the speed is IAS, TAS or GS.