it really depends on the pick up points for the suspension

if you are grafting in a sierra floorpan then the points should be the same as the sierra other than the shock absorber turrets

i'm not sure they'll hake a huge difference at the rear but at the front they'd need to be a bit spot on as they can affect camber and caster

go with the sierra settings and then tweak them with adjustable bits and bobs where needed