Maybe this is just news to me, but I didn’t know this resource was out there. In comparing the updates between two nodes on a cluster, I found out about the “Microsoft Update Catalog” where you can add updates to your basket and download them all at once. I also found the cluster validation wizard lists the same updates as missing.
Not sure if this will be beneficial in all cases, but when trying to match up servers with updates it might help someone. Don’t forget that updates can be superseded and try to trust your WSUS server.