Make your decision well before the concrete slab has been costed and planned. I have seen some shocking floors where clients have decided to polish an existing slab that has had patchy aggregate exposed (or not exposed consistently), hairline cracks and old plumbing locations that have been patched up. One of my clients hated the patchiness of their old slab after the expense of polishing it so much that they ended up paying to have it tiled over! As long as you are clear with your decision well beforehand there should be the proper attention paid to the right aggregate and its location. You have just as much chance of chipping a tooth on a porcelain tiled floor as these tiles are just as hard as a concrete slab. Like a porcelain tile they are very unforgiving on any dropped crockery which will smash. You should also pay careful attention to the threshold height difference between your old floor and your new slab. Ideally there shouldn't be a difference between old and new when the polishing has finished, but this can be hard to achieve neatly.

Sorry to hear that you are covering over those oregon rafters and putting in downlights. The rafters have so much character and ceilings like yours aren't built today due to the expense of sourcing such large, long bits of timber. The downlights are only going to contribute to the blandness of the room. Save your harsh and unforgiving downlights for task areas, not your living areas. With a ceiling of that height I would be considering some nicer pendants, some wall washers and uplighting to celebrate the space and character that you have, rather than making it look like a bland, hospital waiting room. Best of luck, Dr Retro of Dr Retro House Calls

I would go for the spotted gum option to create flow between indoor and outdoor, the social areas of the house. So when you have the doors open, there is a sense of continuity and the spaces feel generous. Monia

Are you talking about a concrete slab? You need to go to a tile shop and ask to see tiles suitable for outdoor use and with a good slip rating. Then choose the ones you like the look of which meet those criteria.