From a practical perspective on the FFS which I am doing now I tried both Flex and TOGA with Engine cut after V1 I found it pretty much easier for me when I applied TOGA and as a friend suggested on airbusdriver.net (A320 Technique page) I smoothly rotate in a slower rate than normal until the pitch is a little above 10 and left the side stick, the aircraft went well. But thanks for all contributors for their valuable replies.
Note:I am just in the initial A320 Type rating at Airbus in Toulouse,and don't have any experience on type.