I totally support the idea of Mike, I would have suggested the same. SOBR is about grouping together multiple storage that receive the same backup job, but here we are talking about a two-stage design, so having one storage per stage is perfectly fine. Also, with this design you avoid to have two copies of the same backup inside the same SOBR, which may be a single failure domain.
EMEA Cloud Architect @ Veeam Software
Veeam VMCE #1