This is how I do it.
I basically do the same thing but I just use the CO2 to get the siphon started
and I don't have the fittings. I just hold the gas line up to the carboy cap till
the siphon starts. I stick a cotton ball soaked in alcohol in an air lock and put that
in the carboy cap to act as an air filter, I don't know if it actually filters anything but it
makes me feel better.