Finally, after a lot of dead endings got it to work.
This is the code that Juicebox displays on Publish.
<!--START JUICEBOX EMBED-->
<script src="jbcore/juicebox.js"></script>
<script>
new juicebox({
containerId: "juicebox-container",
galleryWidth: "100%",
galleryHeight: "100%",
backgroundColor: "#222222"
});
</script>
<div id="juicebox-container">
<!-- Image gallery content for non-javascript devices -->
<noscript>
<h1></h1>
<p></p>
<p><img src="images/IMG_9392.jpg" title="IMG_9392" alt="" /><br>IMG_9392 </p>
<p><img src="images/IMG_9354.jpg" title="IMG_9354" alt="" /><br>IMG_9354 </p>
<p><img src="images/IMG_9366.jpg" title="IMG_9366" alt="" /><br>IMG_9366 </p>
<p><img src="images/IMG_9370.jpg" title="IMG_9370" alt="" /><br>IMG_9370 </p>
<p><img src="images/IMG_9374.jpg" title="IMG_9374" alt="" /><br>IMG_9374 </p>
<p><img src="images/IMG_9385.jpg" title="IMG_9385" alt="" /><br>IMG_9385 </p>
<p><img src="images/IMG_9387.jpg" title="IMG_9387" alt="" /><br>IMG_9387 </p>
</noscript>
</div>
<!--END JUICEBOX EMBED-->
But nowhere does it mention BaseUrl.
Eventually I noticed it did in a script example on the "Using an External Gallery Folder"
So I used that and came up with..
<!--START JUICEBOX EMBED-->
<script src="/wp-content/uploads/juicebox/test_13/jbcore/juicebox.js"></script>
<script>
new juicebox({
baseUrl : 'wp-content/uploads/juicebox/test_13/',
containerId : 'juicebox-container',
galleryWidth : '800',
galleryHeight : '600',
backgroundColor: '#222222'
});
</script>
<div id="juicebox-container"></div>
<!--END JUICEBOX EMBED-->
Which worked straight off.. Please correct anything that is not proper.
I've probably learned a good deal about the process by trying everything out but as with anything to do with Wordpress or Joomla (our other webs use that) it is a bit daunting for the novice to understand enough of new processes to get there.
I was beginning to fell like I should have stuck with the Lite version in jAlbum since it does all this sort of thing for you. But, nothing ventured nothing gained, so I'm happy to be able to use all the additional features that attracted me to Pro in the first place.
Thank you for l your understanding of such user problems and for the excellent guides.