Topic: RAWK Design circle / committee.

[Claire.]

you could wrap them into a flex container set to 170mm wide, then have the grids inside as 100% so they're always the same width, and have your final column in each grid be 1fr so it just takes the rest of the space so if there's any rounding errors it won't be as noticeable.

[PaulF]

I went with some white left border and setting the size of the div directly on my offending lines.
This is why I could never do web front end dev , far too much faffing.  And this is to get it working on a single browser!