So how do I make my bonnet?

[Enoch]

Just finishing off some engine work and a few other bits so have started to think about my bonnet. I have to make a huge bulge in mine to clear the DOHC manifold and cam covers. I have never done anything like this before so am unsure of where to start. I know that all the edges need to be nice and rounded to keep mr IVA happy and so it does not end up looking pants.
I was thinking of making the bonnet with a hole in it so it sits over the engine ok then making up a wooden structure that can be screwed to the bonnet. I could then fibreglass over the wooden bits and finish off with some body filler. Does this sound completely mad? Is there an easier way? I am no good at panel bashing, I have tried it before and just ended up with saome badly dented bits of metal
Any thoughts or guidance would be much appreciated.
Enoch