Well I think choosing an an accent color for your retro kitchen provides an opportunity to give the space a dose of your personality and looks beautiful too.

I do not have any tiles in my current house but if you think about grout discolouring and looking bad.... then I think that might answer your question. My thought - the less grout the better.

I'm thinking you should make them higher as the ceiling goes higher, but that's just my opinion. It's a slight difference in height between the exterior sliding doors but the height difference will be good I think. What'd you end up doing?

Thanks pottsy99 it's definitely hardboard underneath the grey finish, so don't think its ferro-cement. Might poke my head up into the roof space and see what it looks like on the other side