John,
Just for my own "two cents", (at today's inflation, that's .75 cents), along with the other 2 gentleman's very valid postings, I'd add in that "color", while important at times, is not a "set law", in fly fishing by any means!
"The Royal Coachman" has, of course, shot the "Must match the hatch, exactly", theory all to pieces, more times than not!
I'd be more interested in the types of water you'll be fishing on this upcoming trip. (If, I were, you, I mean). If you''ll be fishing moving water, the majority of the time, I'd stick with a single hackle parachute, not only for more ease in tying, but also simply to save materials as well was making the fly buoyant, longer, as opposed to TWO wet hackles to keep dry.
Mainly, though, in the micro-split-second, that any fish is going to have to see your fly, as it rapidly sails past their "window of vision", they are going to be solely interested in the silhouette of the imitation, not its exact coloring.
If you are concerned with the color issue, though, sighting the excellent point made already, about "the undersides of hackles, usually being bleached out lighter", you can soak a grizzly hackle in a strong batch of Black Tea, to help equal out the coloring, staining the underside of the hackle a closer shade to the top.
Whatever you choose to do, do ONE thing........ report back, HERE, and the success of your trip! Have fun, be safe and keep your net full!