How to properly fit dodger?

[lockie]

I had a new dodger (that's a Sprayhood to the poms) made up using the old one as a pattern and reusing the original bows. I thought it would be simple to maybe move maybe one or two of the mountings to accommodate what I hoped would be a slight change in dimensions.

Unfortunately it hasn't worked out (it was a cheap job and I have well and truly gotten what I paid for) and I'm struggling to get the right tension evenly throughout the fabric.

Can anyone point me to a guide to fitting a dodger to get even tension?

Cheers, Graeme