Set the TC to all SMB names. Short, no spaces, pure alphanumeric.
Give a different name to 5ghz.
Set the wireless channels to manual and fix 2.4ghz to 11, 6 or 1.. try each in turn.. they are the only non-overlapping channels.
Set security to WPA2 Personal with 8-12 character alphanumeric key.. longer is fine if you are paranoid.. but seldom required.