I think your in trouble man!
If you are 1wk into 12/12 they are still going to at least double in size.
If that's the case you may have no option but to kill one off.
I'm sure that's not what you want to hear.
But one that yields like crazy is better then two that don't yield shit, because they are not getting enough light penetrating the canopy.
I would be worried about bud rot and mold with them packed in there like that.
I would not do any more training, all that's going to do is make them bigger.
If you are past the 3wks of stretch from going 12/12, then just chop all the growth that dose not reach past the middle point of the plants.
But like I said if your not past the 3wks of stretch, killing one off may be your only option IMO.