For Xfce 4.18, OMG! Ubuntu! has published four distinct clock styles that make use of the additional preset choices.

4 Alternative Clock Layouts You Can Use in Xfce 4.18

This post won't appeal to many, but hey: at the very least it'll be there for me to reference next time I want to rejig the clock layout on my Xfce install.

4 Alternative Clock Layouts You Can Use in Xfce 4.18 - OMG! Ubuntu!