Back to general tech:
The easiest possible way to hit the Missile KB I've found is
JI2 B2KB B1 F34 KB
We all know by now that if you link the B2 to the JI2 on hit it's guaranteed to land, the B1 right after never misses and requires no dash, it also already puts in the B input of the BF3 so you can shortcut it easily, and they're in the air so long off the B1 that it's basically impossible to mistime the fireballs.
"Only" does 40% out of 2 KBs, but if you suck at timing D12s, it's a braindead way to use it.
I don't think it's even possible to miss it unless you straight up let the person hit the ground before putting in your B1.