Chris, what does that mean, "device fingers"? Is that phone settings or the settings in google photos? I have an S5 and can't find anything like those settings, but I am having the same problem and it really makes me miss iPhone....
Thanks, MisanthropicScott, WiFi Prioritizer also worked for me (seems to at least...just added yesterday).
As an aside, I did actually contact Samsung to ask if there were a native way on the device to set preferred networks, and got this reply (several days later):
"Unfortunately there is no...