Then you do not need helium material properties; you instead need to model the convection coefficient. I don't believe that helium properties are going to give you that.
I would recommend posting the following question in the Heat Transfer and Thermodynamics Engineering forum:
"Where can I find information on convection coefficients between various gases and solids (specifically between helium and quartz)?"
That is question you need answered. You may not get that question answered, but somebody could instead provide you some ballpark values.
I'm sorry that I can't answer it myself, but hopefully I have pointed you down a better path.
Regards,
Brad