I notice that `tolerance = 200` for a single-column layout in the article class but that `tolerance = 9999` for two-column layout. But in `ltxgrid.cls`, `tolerance` stays at 200 for either `\onecolumngrid` or `\twocolumngrid`. 

The larger tolerance in the two-column article class resolves a number of problems in the the narrower lines of two-column mode, but it can leave very wide spaces.

So, my questions are: why is the two-column value set so high in article class, and what is a desirable value for `tolerance` in a typical two-column mode?