How to dish a tank - 2

So after yesterday tacking I've started completing the job just welding it.
I've didn't make a very simmetric shape and this is a problem, if you want to do it you need to be sure:
1) The shape must be perfectly simmetric so that when you turn it the shape will fits without problem.
2) you need to cut the tank on the non curved portion, if you cut it where it's curved then you will have a problem when you reverse it since the bending will be in the opposit direction..