my friend have a 2008 2500hd 6.0 VVT sierra...i know they arent DOD engine

so i programmed his truck with the diablo predetor and i sit the rpm shift points at 6400rpms

i sit the injectors @ 3% +
and advanced the spark with 3%

i know the calcualting of the sparke should be in degrees but the diablo uses %

he runs 93 octane gas..is this a safe tune? or should i lower the shift points to 6200-6100rpms?