In order to pull together some specifications for a programmer, I need to come to grips, soon, with how one might encode a links to a digital archival objects via an embedded thumbnail in EAD3.  

I at least need to figure out the number of variables we need to allow for... so, for example, it would be really, really helpful to know how many attribute values overall might have variable values when encoding with a the goal of thumbnail + link as the html display.

I do not know if TSEAD was thinking about embedded thumbnails as links to digital archival objects when developing <daoset> but there seems to be no other way to introduce two links that relate to a single digital object. 

In current EAD, we do this to embed a thumbnail:

<daogrp xlink:type="extended"> 
<resource xlink:label="start" xlink:type="resource" /> 
<daoloc xlink:href="[URN OF EMBEDDED THUMBNAIL]" xlink:label="resource-1" xlink:type="locator" /> 
<arc xlink:from="start" xlink:show="embed" xlink:to="resource-1" xlink:type="arc" /> 
<daoloc xlink:href="[URN TO DIGITAL ARCHIVAL OBJECT]" xlink:label="resource-2" xlink:type="locator"> 
<arc xlink:from="start" xlink:show="new" xlink:to="resource-2" xlink:type="arc" /> 
The HTML result can be seen in finding aids like this one (scroll down to "Inner crater of El Misti, Arequipa, Peru") :

In EAD3, I'm thinking it would look something like this, which is blessedly more straightforward than current, but it still strikes me as a kluge that subverts the intention of daoset:
<daoset coverage="whole">
<dao daotype="other" linktype="simple" href="[URN OF EMBEDDED THUMBNAIL]" actuate="onLoad" show="embed" otherdaotype="thumbnail"/>
<dao daotype="derived" linktype="simple" linktitle="LINK TEXT" actuate="onRequest" href="[URN TO DIGITAL ARCHIVAL OBJECT]" show="new"/>

Am I right that this is subverting the intention of <daoset>?  Can anyone suggest on a more orthodox option?

Any help would be appreciated!