Gotcha, will update within the next hour or so. Thank you for the feedback on it! I spent a while looking at different tags and other info on forums etc, and there's not much information (some of it conflicting) on marking towing services/tow yards.
As of right now and for the past couple of months/past year when I've went by there occasionally, I haven't noticed vehicles outside of the fenced in yard, but perhaps it is better to just mark the whole lot.