How to manipulate symbols (specifically getting open circles) using gscatter?

I am using gscatter to plot distance (distall) and threshold (qthres) data for a range of subjects. That command works fine, but it does result in smaller, filled circles that I typically don't like to use as my data points tend to overlap.

This is the code I have been playing with:

h = gscatter(distall, qthres, subj)

And I tried:

set(h(1),'MarkerEdgeColor','r','MarkerFaceColor','none', 'MarkerSize', 25)

But this does not seem to work -- only the size seems to change. Any recommendations for manipulating the circles here? Thanks!