do I really need the ones he put on top of the brake ?
Yes, because the bolts are at an angle to the caliper. If you didn't compensate with spherical washers under the heads, the bolt head would only make point contact at one side, and it would try to pull the caliper back into parallel with the fork mounting face, which is the thing you're trying to avoid
Yes, because the bolts are at an angle to the caliper. If you didn't compensate with spherical washers under the heads, the bolt head would only make point contact at one side, and it would try to pull the caliper back into parallel with the fork mounting face, which is the thing you're trying to avoid