Rocker gaskets are cheaper than that - I have one here I can send to you for £10 incl post if you want?

Genuine Ford one too

I would personally get the rocker cover powdercoated and normal heatproof paint will eventually crack and look horrid

when replacing rocker cover gasket, make sure all the surfaces are clean and definately make sure you don't tighten it too much as oil starts to seep out