Currently the dynamic-respondr-skin portlet allows you to choose between Static and Dynamic mode. In the latter, you can pick...
Primary brand color
Secondary brand color
Tertiary brand color
But the secondary color is not used in the default skin, and Bootstrap doesn't even support (natively) a third brand color.
Use the secondary color in 1-2 minor ways in the default skin
Eliminate the tertiary color
Introduce some of the following options (whatever makes sense): content-area link color, content-area text color, header/footer area link color, header/footer area text color, portlet chrome border on/off, portlet chrome rounded edges, etc.
Changes will need to be made to the default skin LESS files, as well as the CONFIG form in the dynamic-respondr-skin portlet.