You can get away with the 16px setting, but I feel 24px is spot on. 32px is just BIG. You can change these settings in the main tool-bar package settings section. Go to Settings-->Packages-->Tool-Bar. You'll see the "Gear" Icon. That is where you can change things.
A big thanks to Suda for making the tool-bar package. And for the example code.
And to CakeCatz for making the flex-toolbar.
Good catch. Let us know what about this package looks wrong to you, and we'll investigate right away.