The latest version tries that, I'm not entirely sure if it made a difference because I'm not entirely clear on where, exactly, the variables are used. Plus if I understand LESS's stance on not including a "!default" feature, this shouldn't impact the way variables are declared?

I'm actually a bit unclear on when a variable's value is used. I always kind of assumed LESS and SASS compiled "as they go" so if you changed a variable's value midway through the script the new value would only take effect on further styles and its original value would be used above, but I actually have no idea if that's the case.