Yes, as above the correct way to do it is to list the files you want to synchronise first (with the !) of course and have a * at the end. It’s best if you can have the same list at both ends hence using a .stignore file that is just an include directive pointing at the actual file with the list is the neatest way to do it.
So what I have on each system where the ‘sparse’ folder is being synchronised is as follows…
In .stfiles (you can call it what you like of course):-
// This works as an include list by using !filename to include a file and
// putting * at the end to ignore all files not explicitly included. It
// is used with a #include in .stignore so that the list gets copied to
// synchronised systems
Note that .stfiles has !.stfiles in it so that the file list itself is synchronised. Obviously your list of files would be different.