1.)First of all in the interest of safety and common sense donot use sharp and long screws that will create a hazard 2.) second of all use what the maufacurer provides and 3.) third read article 110. requirement for Electrical Installations A,General And last i would not allow sharp long screws it would be a failed inspection in my book.the self tappers i wire is showing in the picture seem ok if manufacturer screws were unavailable. God Bless thank you for your time.