What is the fundamental difference between the two? On the server side on the service, I am using readerQuotas to accomodate large string lengths (Int32.MaxValue). What is the significance of maxReceivedMessagesize then?
maxReceivedMessagesize is the total size of the message.
readerQuotas are the size of parts of the message for example the length of a string in the message.
You need both of them so be set high enough for your message to go through, often the defaults will be OK.