Hi to all,
I tied a bunch of eggs when I lived in Alaska. Here are some things that worked for me. I use Glo Bug yarn and it worked good for me. Make sure you use heavy shanked hooks made for eggs. I like size 8 hook. The best thread is Kevlar. When you over wrap the yarn onto the hook make sure you really cinch it down tight. Make each over wrap is directly on top of the last wrap. Don't use too many wraps. After your over wraps are complete and you have wrapped next to the over wrap on the front and back make a couple of horizontal wraps around the base of the over wraps and whip finish by hand. I find that whip fishing by hand helps keep the wraps tight.
Here is a link to a tutorial on how to tye a Glo Bug egg
. I don't agree with his choice of 8/0 thread. I got better results with Kevlar as I can pull it tighter.
I have not used the McFly egg yarn but understand it is a bit more spongy.