Can't beat the lawson and harrop stuff.
The Western Green Drakes are different critters than the Eastern Green Drakes we get around here. On the roaring fork and frying pan they are also bigger than a lot of other WGD's and run size 10-12.
When I was out there last I had some good days using a Poxy Back Nymph and a Quigleys Cripple if you're looking for some more patterns. The cripple outfished the duns and really got slammed. here's a pic of a generic quigley's cripple
for a Western Green Drake version of the cripple, depending on what you have hanging around:
hook: dry fly size 10-12 (I actually used a standard 12 and a 2x long size 12 to get a size 10 length but to keep weight down, and use size 10 hackle on the hook to get the right proportions)
thread: olive (or brown)
Tail: olive marabou about the length of the hook gap (or tan antron shuck or 3 pheasant tail fibers)
Abdomen: Olive marabou, wrapped like peacock herl (or dubbed olive dyed rabbit)
Thorax: dark olive antron or superfine or fly rite synthetic dry fly dubbing
Wing: tan deer hair tied in tips forward, butts trimmed to make fat thorax
Hackle: olive dyed grizzly (or plain grizzly) wrapped over deer hair tie down.
I fished green drake paradrakes, and comparaduns too and had some luck on yellow humpies in fast water when I was screwing around, but the Harrop and Lawson stuff that Fyshstrykr suggested would be better bets.
I didn't fish any WGD spinner patterns, but carried some just in case. I tie basically the same style for all my spinners and just vary it for size and color.
For WGD spinners I used:
Hook: 10-12 preferably 3 xfine wire for spinners, or std dry fly if you don't have 'em
tails:brown or medium dun tails,
body: dark olive dry fly dubbing like superfine or fly rite
Hackle: mixed Light Dun and Ginger hackle left in the round to skitter or trimmed on stream top and bottom to float flush in the film.)
The guys at Roaring Fork Anglers (in Glenwood Springs) were really helpful in helping point me in the right direction and giving some great advice, as was Tim Heng at Taylor Creek Fly Shop (in Basalt). You should have a great time, it's a spectacular fishery. Good luck!