This is just a bad layout.

Why wasn't this fully measured so that you'd have NO sliver cut tiles around the design?

the waterjet tile should have covered the entire back wall,

(or, the pencil liner would have gone in the corners, top/bottom, and the waterjet butted up against that).

Having the sliver cut main tiles is too busy looking.

And, a good tile person will NEVER have sliver cuts anywhere. That's called being lazy and not doing a dry layout.

another option,, a chair rail border. These chair rails are usually wider than a pencil

the design should have been smaller so that the main tiles could have had a bigger portion around the accent

pencil lines w/larger cuts or the main tile. the accent would have been a smaller size.

or, scratch the pencils, shrink the waterjet, and do larger main tiles around the accent

The pencil liner and the sliver cuts are too much.

can you back up and take a pic showing the whole wall?

@Beth H. :

Thanks for the feedback. My husband says he fully agrees with your comments and he made similar suggestions (either do full wall or smaller section) but the customer (who is also a family member unfortunatly) insisted on this. They had laid out the tile and this is the size it came out to.

A lesson learned I guess. Admittedly my husband is not a designer so he gave his professional opinion but didnt push back when the customer insisted on this.

I dont have a better picture unfortunatly. Doing the entire wall over is not an option so I guess theyll give the top sliver tiles another go and hope we get an acceptable result.

Once it’s all grouted, it’ll look better. Not perfect, but better.

agree with above poster. grout it. I think it will look perfectly acceptable and the "average" person will never notice.

Shim and drywall the ceiling down to level.