A difficult thread to measure. What type of species do you have? Not really fair to compare say a senegalus to a endi, none the less since I am the first to respond to this thread I will set the bar
Endi-3.25" (I doubt this will hold for long)
Senegal 10" (this one might last a day or so)
Delhezi 12.5"(could be interesting as this is near the listed max size)
Ornate 14" (I look forward to pics of ones bigger than this-