i find i have the most success when i begin the body press motion immediately after whatever string i'm doing, be it 113 or 123. the only tricky part of the b23,123,c.grab is doing the 123 early enough. if you take your time and do the c.grab correctly its an easy buffer. if i screw up the c.grab it's usually cause i tried to do it too fast.
i don't use the AA grab at all. probably should, if only as a followup to b112. early on one of my biggest problems was coming down from a jump, going for a d1, and and the fucking AA grab coming out. when you're going for a d1, the AA grab is truly the worst possible move that could come out.
it's because you hold back to block. in MK9 i never held down-back when ducking, just the block button. now that i'm holding down back the game reads my d1 as db1 with disasterous results. it took awhile to consciously adjust to this and it doesn't happen nearly as often anymore, but i'm kind of hoping for a patch of some sort. i sure hope it NRS thought holding back to block was worth it to attract all those SF players who immediately dismissed Injustice for the so-called "dial-a-combos" anyway.
input issues like that aren't a good reason to not use Ring Toss, but there's also the issue of the direction you throw your victim is dependant on where you grabbed them in the air instead of choosing yourself.
for now i'll try to implement 223+db1 for the range on the string and b112+db1 if i want to throw someone behind me without burning meter.