I would be very careful with this batt. It is only within the last few years that companies such as Hobbs and Quilter's Dream have come out with washable wool batts that do not require special care. These two brands of wool batting are, I believe, both needle punched and treated with resin or other surface bonding agents to prevent bunching, shrinkage, and bearding.
Historically the recommendation for wool batting was to encase the batt in cheesecloth before layering. This was to help prevent bearding, which tended to be a problem with wool. Once bearding starts in a wool batting quilt, it is impossible to stop.
Another recommendation for wool batts was to hand wash in cool water. Wool fibers are shaped somewhat like hooks. If you have ever mistakenly washed an adult's wool sweater so that it shrank to a child's size, this happened in part because of the hooked fibers. When wool fibers are agitated in the presence of hot water and soap, those hooks start interlocking; this is what causes the massive shrinkage, or "felting" of the wool. (Felted wool is very nice for certain applications because it does not ravel, but it would be disastrous inside a quilt.) The Hobbs and QD batts have been treated to have a maximum shrinkage very similar to cotton batting. An untreated wool batting can shrink much, much more than this if specific washing instructions are not followed.
It sounds to me as if the wool batting you purchased has not been processed with the new technology, so I would absolutely not trust it to behave in the same way that Hobbs wool or QD wool battings behave. It is much more likely to behave like the old-fashioned wool battings. This means it probably needs to be encased in cheesecloth, probably needs to be more closely quilted than either Hobbs or QD (to prevent shifting and clumping of the wool, and also to inhibit the wool fiber hooks from interlocking), and needs special care when washing.
I think if you Google wool batting for quilts, you will find some of the warnings for the older type of wool batting that has not been needle punched and bonded.
p.s. That is a really beautiful quilt top! If using the wool batt, you may want to also consider using a light colored fabric for the backing. That way, if there is any bearding, it will not show up the way it would on a dark colored backing.
Edit: I found the following FAQ that explains a little more:
http://www.masterstech-home.com/the_...attingfaq.html
Also, if you Google "wool batting cheesecloth" you will get more information about untreated wool batts.