Chain tension and tensioning a chain

I don't want to start a new thread...

Any pointers on how to centre a chainring on a set of cranks. I have done the sheldon brown method but it had little effect. There is quite a difference between tight and slack (chain) on my bike at the moment.

Is it likely the cranks are bent? The chainring is a TA Alize brought as new.

it is unlikely that the cranks are bent, but if they are it should be easy to see.
If you spin them they should wobble.

I havent seen the Sheldon menthod of chainring fitting. But Id just say use common sense, leave the bolts half tight and give it a few spins with a snug chain on, it should centre itself, then tighten up at opposite corners.

You should even have to do this if you have a modern/decent pair of cranks, as the chainrings fit very accurateley anyway.