Problem with animated brush in GIMP

[Zaianya]

Hey y'all!

I'm working on a city map, and just picked up RobA's incredibly awesome animated city buildings brush. Unfortunately I'm having some trouble with it, namely in getting it to be the color I want. Essentially, in his original thread, there is an image demonstrating the brush's use. One of the options in that image is "stroked using the 'color with gradient' option," and that's what I want: to use this brush in a color of my choice. However, that's not working. In fact, I'm just going to illustrate exactly what's happening with a series of pictures.

When I use the brush normally:

Map1.PNG

But I want to stroke, not merely brush. So I go to "Stroke Selection":

Map2.PNG

...and the result is below:

Map3.PNG

Anybody know what I'm doing wrong? As you can see, not only can I not figure out color, for some reason the size goes completely wonky when I emulate brush dynamics.

EDIT: I should add that, while I can certainly select and replace the color, I don't want to do that because I lose that cunning little border that the brush adds to the shapes. I very much like that.