How about two colour coding systems:
Blue = Independent bike shops.
Red = chain bike shops.
Darker colour for higher quality/more repute/etc.
Lighter colour for less quality/lower repute/etc.
Simple and effective... if it's a dark colour it will stand out, and you'll be able to see whether it's a chain shop or independent and set your expectations accordingly.
How about two colour coding systems:
Blue = Independent bike shops.
Red = chain bike shops.
Darker colour for higher quality/more repute/etc.
Lighter colour for less quality/lower repute/etc.
Simple and effective... if it's a dark colour it will stand out, and you'll be able to see whether it's a chain shop or independent and set your expectations accordingly.