Nohub is a plumbers best friend. You are over engineering this. I don't know about your neck of the woods but we don't use pvc on drains where I come from. Also, I've never seen a white plasic pipe of any type on wastelines from toilets here in CA. PVC gets used in condensate drains for A/C commonly but not waste water from toilets.
Listen to the nohub suggestions. They are spot on. Wholesale houses don't stock every type of nohub connectors. They just stock the most common ones. But in their catalogs, there is always a listing to connect any combination of sizes. Why aren't you trying to do this with ABS? I'm baffled as to why you are trying to use PVC.
