i can confirm that your version of plone.recipe.zope2instance resolves most of the problems i was seeing. the client's zope.conf has the correct blobstorage storage declaration. thanks!
there is one remaining problem. i include a "var =" setting in my [client1] and [client2] stanzas, expecting that would set the var directory in the <zodb_db><zeoclient> section of the resulting zope.conf, but that does not happen - the var setting continues to be the default.