Do all 10 chairs need to be at table all the time or can it be 8 chairs and 2 you bring over from somewhere else for large sit downs? DIAL UP YOUR CHAIR sizes to be proportional to table so, as to not look like child size chairs. Restoration Hardware furniture is over sized and generous proportions compared to many other retail sellers. Just any chair could be easily dwarfed by the RH table and look tiny. Here are a couple of my favorite modern chair makers KNOLL Brno flat bar chair which can be bought at auction and recovered in leather or vinyl of your choice and David Edward Furniture made for corporate, resort and colleges and available through dealers, I am showing here as a "host chair". Other "host" chair items possible of course. I just like this one.

Not sure if you can make you current table height adjustable and what's involved with making the banquette wide enough for lounging but here are some pictures. Places that fit out caravans etc might be able to help with the mechanism for the table and don't forget that stools can double as seating and tables too for added functionality as per this recent Houzz article..[Ultimate secret decorating weapon[(https://www.houzz.com.au/magazine/is-this-the-ultimate-secret-decorating-weapon-stsetivw-vs~55543429).

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?

If you have a bit of storage space then consider buying a couple of inexpensive easy wipe stackable chairs (eg ikea) for visiting kids to use. Parents and you can then relax and enjoy the meal without worrying about your upholstery. Alternatively, tie-on seat cushions will give some protection plus a height boost for little ones.