Congratulations on a fine Blesbok. You should be able to go the SCI website and at least get info on the top ten for each species without being a member.
Remember SCI is very different than B+C, and there can be multiple animals in the book with the same score. This doesn't take anything away from the fine animal you harvested, just don't think they are similar systems. SCI animals don't have to be taken by fair chase, either, so some farm raised and fed animals end up in the top slots in their book. Makes it tough to really understand how your blesbok stacks up compared to other free ranging animals.
Bill