It will be set up to use AI mags. Will the creedmore or 6.5x47 fit in the AI mags?
The CM and x47 will certainly fit in the .308 AI mags. What you are trying to accomplish is to be able to reach the lands with the VLD type bullets and chase them for a while as the throat wears. You can do that with a .260 and a 2.8" box
if it is properly throated but at 2.8" you are seating the bullets really deep in the case and the ogive is getting mighty close to the case mouth. For those reasons, in a 2.8" box, I'd prefer the x47 or CM. If the AI box allows a 2.9" or greater COAL, a .260 would work fine if you prefer it over the other two.
John