Headlight filler

[Reedy]

I'm looking to remove the headlight assembly in my track bike and replace the gaps with some pre molded cut outs. Is there a specific place that would sell these for specific models or do they need to be custom made

[Damon Z1000]

take the headlight out, cover it in tape and fibreglass over the tape.Let it dry and peel it off.
Gap filler extraodinare