Default fonts on Mojave (5539)

When I've updated to build 5539, I've needed to reset the fonts after I've made some changes that were necessary with previous versions of MailMate. I've noticed various issues regarding default fonts with this build 5539.

After "Preferences > General > Reset Fonts"

1. In the mail list, there is almost no margin between the individual messages. The font looks small.
   
2. In the Mailboxes pane, there is almost no margin between the individual mailboxes. The font looks too big compared to the icon size.
   
3. In the message pane, the font is really small as a default font.

If then went to change the fonts via "Preferences > General > Show Fonts"

1. If I select the mail list and change the font size from where it is to the exact same value, there is suddenly some margin between the messages.
   
2. If I select the Mailboxes pane and change the font size from where it is to the exact same value, there also is some margin between the messages.
   
3. If I select the Mailboxes pane and change the font size from where it is to the exact same value, the message text size is OK.
   
4. The icons in the Mailboxes pane are now a little bit too low, so I've tried to decrease the line height delta from -7 to -9, but this doesn't solve it.

After restarting MailMate, the font size from the Mailboxes pane is back to the default.

Also, the new color of the count badges in the Mailboxes pane is really high contrast. I liked the softness of the previous ones, now it's the dominant visual element in the pane. Also the darker grey of the background seems unusual.

Please let me know if you need me to test something or if you need screenshots/screencasts of the process.