I'm going to copy/paste what I said in the other thread:
I tried using my standard Wii playing position ie. my right arm/hand resting on my right leg to provide stability and quick and accurate aiming and then tried to hold the DS3 in my left hand.
If we only need to use the left analog stick on the DS3, then there's no problem at all, you can have a solid grip on the controller and use the stick without any problems but if we need to use the L1 and L2 buttons then the hold become very uncomfortable and unstable with two fingers used for L1 and L2.
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