I also use (and recommend the use of) the 'long C#' fingerings wherever possible (with the 8ve key, oox|xxx or oox|xxxEb or oox|xxo or oox|xoo or oox|oxo or oox|ooo) to add substance and raise the pitch of the open C#, and the fact it keeps the right hand fingers down when going over the break to smooth out slurred leaps between open C# and D,Eb,E,F,F# and G.
Though it won't work on some sopranos that have the split open C# vent where part of it is closed by the 8ve key (except on the Yamaha YSS-475, 675 and 875 sopranos which have done away with it completely), and also the Selmer Series III altos with the open C# vent - which isn't much of an improvement of the open C# anyway, and more likely to be a headache when it goes wrong (and means C# is best played as an open note as opposed to being played with any other fingers held down - for people like me that like to put fingers down in advance when crossing the break on certain intervals it makes things very ermmm... interesting).