This was my mistake, yeah, it's -4. Completely safe without IB, sorry about that.
6A will work in most cases against j.C, provided they aren't using it from the heavens or spacing tool. It'll be j.C as a jump in. But j.C has been able to clash and even beat 6A in some cases since CS2, this isn't anything new really. 5A anti-air works too, but more against sloppy jump ins rather than all the time.
You can often hit Ragna out of Deadspike, provided your reactions are that amazing. In most cases, jumping over it is best. Jumping after blocking it in the corner puts you at risk of being 5B'd or air grabbed, both of which lead to 4k.