Do you mean add another empty floating container and use that to control the width of the columns. My problem is more the columns width in each table rather than the table width.
As you can see from the two screenshots from above, the table widths are more or less the same, it's the columns which are not aligned well
Yes, to align the columns you will need to independently select each table and adjust the width but I was hoping you would see where I indicated with a red line that you can line this up using the edge of a sheet like you would use a ruler.
The problem with floating sheets is you don't have a consistent start/end point for each sheet, so eyeballing it is the best thing on offer.