I am just about to start modifying the nosecone I got. It's for a std chassis but mines a 442. I'm finding it ok for with and knew it would nver fit in height. So here's the thing I've got two options and bear in mind it's a XE engine.
1. I could split it through the middle and extend the nose opening to give more airflow through the radiator. This does not allow any where for the No plate
2. I could split it below the opening and form a flat area below to mount the No plate on.

Or you could put a stick on numberplate on the top (sloping part) of the nose cone at the front.
Also makes it a little harder to lock a laser beam on to it
Or a smaller bike sized one

Been up looking at it again and I think it would look a bit wank without making the radiator opening larger. Stick on No plates are Illegal are'nt they

Best way to make it wider is straight down the middle.....before you cut it make a simple mould of the middle section covering enough area to allow it to hold the nose after you have cut it.....fasten it on then lay up inside......doddle apart from the fettling bit to hide the surface.

my only concern would be getting the proportions right without it 'looking' stretched if you know what i mean.

why do you think the aperature needs to be bigger? the cooling should be fine with a standard one, is it to cover the bottom rails of the chassis or other reasons?

Not wider Triton but higher. Yes to cover the bottom rails Ned. It just looks as thought it's hanging in mid air at the moment and as it's a 442 the proportions are not quite right.