Also I might add that it is important to be patient and NOT buffer your inputs (e.g. entire BB:B46BB:B string should have precise timing don't mash the buttons) Time them steadily and press 4 once your see the appropriate move hitting the opponent and take it fom there (4 being the initial part...
We all know how important iPR is for Raph when it comes to optimizing his play. The problem is that execution isn't necessarily easy for this nifty little technique. As an example, a big problem for many attempts at 6B iPR BK or WRBB iPR BK is that PR 6B will occur even if it appears like you...
Following on what Lovelain writes, I think that 6[A+B] and 6A+B have a lot of potential. Charged version jails and is -2 on guard and STN on hit. Condition the opponent with the held version to block, frames for 6A+B are -2 on guard and +8 on hit. This is great bc if they block then 6B can still...