That's an interesting dilemma. I would be inclined to go with the dark grey chairs because: - the chairs will be under the table surface most of the time, so it shouldn't be "too dark" when combined with the dark grey sofa; - the dark grey should tie in well with the sofa; and - the dark grey will provide a nicer contrast with the concrete table surface. Does the store you're purchasing from have a returns policy? If you explained your dilemma, they may allow you to take one of each colour home to see which colour works best in the space. Alternatively, can you go to the store which stocks the table, see what other chairs they have in the showroom and see if there are some light grey and dark grey variations that you can try in the store?

We have these and they’re really comfortable and practical. They clean up easily and can be used outside if you need an extra seat or two for a bbq (but don’t leave them outside). The Eames side chair with Eiffel Tower base. There are other bases. This isn’t our place but it shows them with a coastal vibe. We only have one dining area so we use them for every meal including formal entertaining. We’ve had them for a very long time and they have held up well. But get the originals, not the knock offs. There is a difference and it’s unfair to the designers to knock off their intellectual property. It’s a bit like buying a fake Rolex. https://livingedge.com.au/products/eames-moulded-plastic-side-chair-dsr-white-eiffel-base-alpine-shell I also second what dr Retro said. Love the Masters Chair. It’s a modern classic. I need four additional chairs for my new place and I’d consider them but I need something stackable. There are other great plastic chairs out there and they could be perfect for the type of feel you are trying to achieve. But try them out and make sure they’re comfortable. You and your guests could be sitting in them for hours at a time.

I would wait to actually until you move into your modern home and then choose your chairs . You will be able to visualise the look better with the walls , flooring , lighting , other furniture and your art work . Keep your lovely table . Others will give you an idea as to what might suit , so you can search and mull over ideas .

Phoebe in Vic the homes were called Merchant Builders style & in NSW it was Pettit & Sevitt style (I think?), both after the building companies that pioneered the look. But more builders than those 2 built in an evolved style of mid century modern homes in the 1970's & 80's. in Vic another popular building company was Fasham Johnson, which has now dropped the Johnson & still exists building updated version of their 80s look - some features are timeless. I grew up in a Merchant Builders style home in Melbourne (Nillumbik Shire) 🙂🏡