I don't know how hot it gets in Auckland in summer (I've only ever been to NZ in winter!) but if it gets hot, then go for a pale colour. Dark roofs should be kept for cold places!

We just stained our section fences with Wattle Ebony from Mitre 10. Was looking for a charcoal color too, not much flexibility in color options with stains from the shelves at store. We sprayed on, rather than brushing. Is cost a concern? One of our to be neighbours was doing there fences at the same time with paint, he said he used nearly 100L of paint for 2 coats, we used nearly 50L in 2 costs - had similar amount of fences. I've included photo of it after the 2 coats

Looking at the bench , I assume that aged look is what you are going for ? How artistic are you ? I'm thinking you'd carry on in a similar vein -- paint the trim in white , but while its still damp ( so within say 30 minutes ) dab on some off-white and even buttery cream , using a sponge , in a bit of a 'rub' pattern . Likewise , I quite like the faded blue jeans look on the sill -- thats a bit harder to do , but maybe a cream base , then thin the blue with turps or water , and also sponge it on , but basically in solid rubs , like you were nuggetting your shoes .

Have you tried the Dulux Visualizer. I have used this personally and found it to be quite helpful. It allows you to take a photo of your home and then experiment with different colours to see what works best. Another option you might consider is the Sherwin-Williams ColorSnap® Visualizer app. It allows you to upload a photo of your home and then try out different paint colours and combinations to see what looks best. I hope this helps!