I would do a glass splash back [ this can be painted in your color choice to suit the decor ] - taking from the bench top up to the bottom of the range-hood on the wall of the stove. The window is beautiful and I would give anything to have them in my kitchen. I would probably paint OR stain and apply marine grade vanish to the would so that any moisture would not be able to ruin the wood. I would also put herbs or flowers there. Could it be made into a servery for outside maybe ???

I think we are going to use the white subway tile to keep the budget down as I priced new tiles and it would blow out the budget. Really like the contrast grout idea to add a bit of texture and pattern. My partner is a builder and he loves the reclaimed wood shelf idea as we have a lot of spear old wood left over from the renovation. We have made a dinning table and fire place mantel from it already so it would tie in really well.

The taupe countertops are nice. Have you seen all the new choices of backsplash tiles that are available currently? There are so many beautiful ones, there isn't a need to settle on white subway tiles. Venture out to the big box stores or flooring showrooms and take a look... There are tile caps of all sizes to finish off the ends. A nice one is called a tile liner, and it's about 1/2"-wide. There's also metal strips that can be laid in to finish the tile, it looks very nice. They are called: Schluter Systems 0.375-in W x 98.5-in L Aluminum Commercial/Residential Tile Edge Trim and can be found at Lowe's. They come in different colors.

I would look at colour samples next to actual sample of the schist to be used. Take that to a local paint/render shop and look at them together. Looking at your image, the schist looks to be a golden schist rather than a grey. Is this just the way it has been shown? I would check with the suppliers for the actual colour of stone to be used as there are a lot of possibilities and the colour will affect your colour choice for the plaster. Here are a few websites showing some schist colours: https://www.worldofstone.co.nz/stone-mason/stone-masonry/schist https://wanakastone.co.nz/style/ Also consider the visibility of your mortar and its colour. Keep in mind that depending on your render system, you may be even more restricted in LRV, as some systems require an LRV of no less than 40%.