I’m not exactly certain on this but it appears the grades have names rather than numbers. The model numbers within each grade may overlap so you can’t map a range, only an individual number. Are these grades correct? I'm guessing here:
Grade 1 – Bentley Place 9012-9081
Grade 2 – King Street 9011 – , 9049, 9050, 9070, 9090
Grade 3 – London Park
Grade 4 – Grafton Square
Grade 5 – Jullian Harbour
Grade 6 – Sunset Gables


Echo Mountain Spring is in Sunset Gables, do you have an opinion on it? I copied this description from the website:
9593 Aniline: Echo is produced with a soft, oil tannage to provide a rich, vibrant pull-up effect that won’t lose its luster when pulled tight to create rich contrasts. Echo is topped with a paraffin wax to create a clear, transparent surface that will continue to allow the leather to burnish and polish over time. With Echo’s unique natural appeal, shade and grain variation are to expected and appreciated.


And finally do you perchance have a traveling set of BY leather samples. I'm beginning to feel myself run ragged.