No the quickest way is via the bwlch... that was the record route.. the film shows otherwise.. but that was filmed afterwards..
The ridge is nice, but its loose, probably more serious than the East ridge due to the looseness.
I'm not sure of the quickest route actually through the cwm.. I descend then swing left and run down tributaries until I hit llyn glas? the one with the tree on the island anyway.. and then descent across the outflow that takes you down to the path which runs down cmw glas mawr and through to innys etws..
But I think it might be quicker to go more direct, staying right of the llyn...
and from the bridge just follow the road... its about 1.5 miles gently down hill.. so only 10 mins or so.. there is a path up the hillside but its sketchy and much slower..
I used my way when guiding it as its pretty good underfoot and avoids any crags.. and also a very logical route to follow if clagged in.. you can get a bit crag bound if you lose the line the other way.