No problem--no offense was taken and none was intended. Soul searching is a good thing. Remember, it's your call, and your conscience should guide your actions.
Brown trout eggs tend to be golden yellow, while rainbow eggs often have an orangish or reddish hue. Both are about 5-6mm. Brook trout eggs (in case you're interested) are usually paler (kind of a creamy yellow). Old (unfertilized) eggs develop an opaque whitish color.
You definitely want to keep the egg dead-drifting near the bottom. If you're using Glo Bug yarn, the buoyancy of the yarn tends to work against this. Some tiers add a bead, but I prefer to add weight to the leader fairly close to the fly (about 6-8"), or use a less buoyant material. (You'll still need weight, but it can be placed a little farther up the leader.)
As for adding a nymph dropper, it's up to you. It may be a way to sort out the trout's preference on a given day, but I prefer to fish a single fly whenever possible. Two flies always complicate landing and release, and may increase the incidence of foul-hooking. To alleviate any possibility of the fish swallowing the fly, you definitely want to use some sort of indicator when not sight-fishing. In either situation, give Zen-like attention to your drift at all times.
Avoid disturbing redds and try not to fish to actively spawning fish. (You're looking for the fish that are eating eggs, not laying them.)
One last thought on Jason's point about unconventional imitation. I have heard a few anglers express a form of "aquatic invertebrate" purism (which would preclude imitating fish eggs, but not, I assume, insect eggs). That would also seem to eliminate terrestrials, so let's say "invertebrates only." But then you couldn't fish streamers, which imitate aquatic vertebrates. And, without getting into the whole when-does-life-begin debate, aquatic vertebrates are what fish eggs become. Do you see where I'm going? There's nothing wrong with drawing a line somewhere if you like, but getting all exercised about exactly where that line is drawn seems a little silly.
Personally, if a trout eats it, I've probably tried to imitate it at one time or another. When I was a kid, I watched a fine trout eating mulberries that had dropped to the water. I went home and tied my best attempt at a mulberry imitation (sort of a purple Glo Bug, except it was tied with deer-hair). Later, I caught the trout. I didn't think I was doing anything wrong--in fact, I was pretty proud of myself. Of course, this was violating all of the aquatic/invetebrate/vertebrate rules.
I don't know. What do you think? Is imitating vegetable matter taboo? :)