In reply to Jamie B:
Hi Jamie, regarding the grade, I know of a few folk (myself included) who think the direct finish (the original Hamilton/Anderson line) is a full grade harder than anything lower down on the route. Since the route is widely thought of as sustained tech 6 it seems logical that the direct finish must be around the tech 7 mark.
The link below is to a post which supports this view (and which may help with your routefinding problems). It was written by Nick Harper after he and Robin Clothier failed on the direct but were able to complete the route by the variation instead (which also suggests the direct must be harder than the variation):
http://yorkclimbers.com/profiles/blogs/stob-coire-nan-lochan-glen-coe
At the time, Nick and Robin were climbing a lot of tech 6 - the post above mentions two V,6's in the Cairngorms climbed two weeks earlier, and then after Crest Route they went on to do Gargoyle Wall, West Chimney and Scabbard Chimney, all apart from Crest Route being climbed without any reported difficulties:
http://yorkclimbers.com/profiles/blog/list?user=05vgnsf2ezr1x
I found a post on here from French Erick regarding his thoughts on Crest Route, Chimney Route and West Chimney:
"Crest is definitely top end of V,6 and WC not V,6 in my books. Crest is easier than Chimney R. So why not WC IV,6(6 for raeburn's chimney) Crest V,6 (with the express description of traversing left after the belay of P3 the small ledge on the crest...direct is very gnarly and not tech 6) and Chimney R VI,6.
That is how I will personally think of these 3 routes regardless of what any guide books say."
It supports your idea that Crest Route should be graded separately according to the finish that's chosen, and that the guidebook description should reflect this.
BTW, ask Al Halewood or Mike Pescod about Crest Route - Mike's done it a few times and he and Al climbed it together by the variation finish in 2010. Link and video:
http://alanhalewood.blogspot.co.uk/2010/11/my-first-proper-route-of-season....