Is a person who knows that magic is disbelief (kufr) yet still goes to sorcerers to have magic performed, considered a disbelieving apostate for participating with the sorcerer in his disbelief, or is he merely committing a major sin, knowing that he does not deem it permissible to go to sorcerers, nor does he claim they know the unseen, nor is he pleased with the polytheistic (shirkiyyat) practices involved in magic?

A person does not become an unbeliever merely by going to a sorcerer. Rather, they become an unbeliever if this is coupled with the belief that the sorcerer knows the unseen, or if the sorcerer commands them to draw closer to the jinn by sacrificing or performing similar acts of disbelief.

Not all magic is disbelief. Some of it is disbelief, and some is less than that. If it involves a saying or an action that necessitates disbelief, then it is disbelief; otherwise, it is not.