Colour Luminosity/Contrast for form inputs/controls/components

I'm looking at contrast requirements for a client regarding form 
controls, radio buttons etc for a client, and WCAG does not seem to 
specify them. It seems 'implied' that 1.4.3 is relevant and there are 
techniques that touch on the subject (G183, G182, G111) but nothing 
definitive like.

"If you have an UI component/input control, or radio button that a VIP 
user needs to see to select/interact with the luminosity requirements 
are x."

Am I missing something? Or is this something we need to address?

Thanks

Josh