> But you also have to decide at what point to hard wrap each line based on a max line length

Exact and strictly enforced max line length IMHO unnecessary. Too wide code is hard to read, too narrow too but in between there is a wide range of acceptable values. When possible I treat max length as a recommendation, not hard limit.

When you don’t have a hard limit it’s not a problem if code added by someone who uses visual tab width 2 will go over 78 characters in the editor which tab width set to 4. Equally it’s not a problem when someone using 4 will make a line break sooner than one using 2.