The longer the thicker - so at 6' I imagine a mature brongersmai would be the thickest of the three. Kali had really stressful transit and it took her a few weeks to get acclimated in enough to start eating - the other two ate right off the bat and have only skippped meals while in shed. Thas a terribly small sample to go off I know. And our son's Black Blood has similar temperment, Satanic - almost afraid to say he's the most tractable snake in our house.