More granular customization between dirvish-side and normal dirvish buffers

[gekoke]

I would like to include file-size in dirvish-attributes, if it weren't for the fact that it makes dirvish-side incredibly cluttered:

In fact, I've previously felt the need to customize both dirvish-mode-line-format and dirvish-header-line-format separately between normal dirvish buffers and dirvish-side buffers as well.

It would be nice if dirvish could be configured a bit more granularly depending on whether it's running as a "normal" buffer or as a buffer in the side window.