One thing that I noticed in this matchup is that using Tager's pressure strings is not a good idea, as Ragna can just Inferno Divider out of it.
Against Ragna's pressure, if you see a Dead Spike coming out, you can 360A him out of it, and it doesn't need to be on an IB.
Try not to overuse sledge either, as a good Ragna can see it coming and get a CH combo on you, and same goes for 360's if you don't time it right.