Cathie, congratulations on finishing the tapestry!
Let me say that blocking can be your friend. I resisted blocking after my unsuccessful early attempts but through the link at Kathy Spoering's blog here and also Pat Williams' encouragement I have been happy with the process. I don't block everything I do, especially the ones that are 60" or so is either width or length. But those that are under 25" or so I have started blocking. Even if nothing needs to be shrunk to fit (and that's the key... shrinking the wool weft, not trying to stretch it) the pressing gives a crispness to the surface that's nice.
I've briefly described about the way I block on my website at this link.
Also, if you've watched the YouTube video of Felix Haspel that Pat posted a short while back, you'll see the tapestry artist steam pressing his tapestry.
Good luck with the finishing off of the tapestry... and be sure to post a photo to the blog, if you could!