Just a quick post to show the part that I made over the weekend, from the mould. Not everything went to plan but I'm very happy with the resulting part and its so light.

Look like a fun project

If it is a radius that is visual I would actually choose to do it in filler, not take the quick option of plasticine, as with platicine (or yellow wax) it's fine for making fillets on flange edges etc, but the highlight is never quite perfect, and can ruin the look of the finished part if you don't rectify this - best to get the buck right.

My advice in general with mould making is to make sure all your buck surfaces are flat and highlights nice and even; correct everything you can on the buck rather than waiting to do it in the mould, especially stuff that is external on the buck and internal on the mould.. however don't worry too much with going mental with 1500/2000grit wet and dry before polishing (but do polish like hell!) as the mould surface will always come out with a slight ripple (like mild orange peel in paintwork) which you can correct with wet and dry on the mould surface.