Kevin,

while I never investigated a detailed list of options, many of the
smb.conf changes get effective without restarting the server jobs,
i.e. by simply disconnecting and reconnecting to the server.

My personal and in no way authoritative "rule of thumb" is "changes
to share definitions just need a reconnect, changes to globaly style
parameters better have a job restart".

However... as Windows and SMBD tend to do some caching on some of
their data structures, it sometimes helps to use smbstatus to look
up a client's associated SMBD process and send it a kill signal in
the shell, to force the next client access relaunch a fresh child.

Lars.