Cake job, just bolt on spacers and go (well clean and some antiseize on mounting surface). They aren't spacers with extended studs, they are bolt on. I've run lots of cars with bolt ons and I wouldn't question them as long as installed with care.
Third attempt at posting... I apologize if it ends up with multiple submissions.
Anti- seize? My spider trax specifically said to use red locktite when mounting to the axles.
Am I misunderstanding what kind of spacers you're using?