Simple way to create a vertical data scale bar

I would like to create a 100 mm-high vertical scale bar somewhere inside this plot, which has units of mm on the y-axis, and time on the x-axis:

 gmt psbasemap -R2010-01-01/2021-01-01/0/1000 -JX4i/5i -BWSen -Bpxa2Yf1O -Bsxf1Y -Bya100f10+l"North (mm)" -pdf map

I identified two options but ran into issues with both:

pscoast has a vertical map scale, but it really doesn’t like that the axes aren’t geographic.

wiggle can create what I’m looking for next to data traces, so I could create some fake data and use that scale bar (this might be a pain to tweak), but it’s hard to understand how the -Z scale value relates to the Y-axis of my plot. The example uses -Z100i but what does this mean?

Something like this?

gmt psbasemap -R2010-01-01/2021-01-01/0/1000 -JX4i/5i -BWSen -Bpxa2Yf1O -Bsxf1Y -Bya100f10+l"North (mm)" -Lg2012-01-01/150+w100+lmm+v -png map

This is perfect, thanks! I missed that psbasemap has the -L option too.