Your concept will work well in Colorado and collar hackle patterns are universal. For ultimate simplicity, you could use a very limited color selection - Adams grey body and grizzly hackle.
Personally, I prefer parachutes. They are easier to see, float well and seem to work better for some hatches. Standard parachute patterns catch a lot of fish, but I use Klinkhammer style curved hook parachute patterns more often. In fact, I fish curved hook parachutes all year long in Colorado, varying size, body color and thorax dubbing. I even use this style for ant patterns.
I'll add another vote for the CDC&Elk/deer which only uses CDC, deer hair, hook and thread and can be tied from teeny to pretty big. It works for caddis hatches, mayfly hatches and as a searching fly. I don't think you need any color variations, so just a good selection of sizes.
If you can stick to this simple scheme, my hat's off to you. Although I aspire to simplicity, I must confess, I'm a pattern junky.
Good luck!