Thanks for the assist from this forum.
Finally finished mirror, with 24" monitor, pi zero w.

@arthurgarzajr Being the newbie that I am I typed “bottom-bar” for location. Worked on it for an hour before the “-” was replaced with “_”. Amazing how one letter can use up your time. No the module is working fine now.

@maestro82 Got it, a little trail and error.

@Mykle1
So by playing (I do mean playing as I am a newbie) with the MMM_WunderGround.css file, discovered:

.MMM-WunderGround .weather-icon (is the small forecast icon)
I was able to adjust size by changing the width.

.MMM-WunderGround .currentWeatherIcon (is large symbol next to current temp)
I was able to adjust the width and height % to change size.