Bob,
If all you are doing is a border then color case and leave it alone. The grey shows the engraving best but if only border there will be too much grey on the large unengraved surfaces. If you want to do grey we can talk and I will tell you how I did my Fraser. French Grey is incredibly easy to achieve. If you want we can do at my house. I'll be at the show on the 18th wandering around or PM me and I'll give you my phone number.
Glad you are having Roger do the work, he did my Fraser