As there currently are two different limits, I think it would make sense to have a limit for line 1 and another limit for lines 3-n (as the second line usually is blank and thus doesn't need a separate limit). Alternatively the second limit for lines 2-n for those who put text in the second line.

Please excuse the rude language. As for everything regarding coding styles and standards, for me the commit message lengths are only a recommendation. Different projects will require different limits for commit message header and content line lengths, which is why I'd expect them to be configurable, just like in TortoiseGit and other Git utilities.

This option is already enabled, but it only applies to the compose window. It would be nice to have the same font being used for displaying the commit message of existing commits.

It's still not possible to configure the line lengths, which makes the line length guides kind of worthless.