Thanks guys, I'll order the zeiss caps.
@secondofangle2 I have both MKM and Aadmount caps. In my opinion the Aadmounts are better. They seem more solid and don't flop around in the wind like the MKMs do.
I want some for my S5 and I'm wondering they're high quality. Aadmount aren't much more expensive, should I try and get those instead? The aadmount aren't listed on the website yet, but maybe if I give the owner some measurements, he will make them.