A bivy and more cord would take up too much space, resulting in my kit not being carried. 
I sometimes end up 5-6 miles of the road while tracking deer, so I really feel that having a few compasses is a good idea. Normally I would carry two, one pinned to me, and one in my pack, but I wanted my kit to have one as well. 
I like the mag. stick because its versatile, and the spark-lite is good one handed. I usually have a bic in my pocket anyways to check wind direction.
Thanks 
Look at a smaller diameter cord, such as a 2.7mm cord.  A little more expensive than 550 cord, but you can carry more in the same space.
You may not be able to strip the lining from it though.