Found this recent review on OPT website confirming binoviewing works:
http://www.optcorp.com/review/product/view/id/452/
Also found this old review from IceInSpace:
http://www.iceinspace.com.au/forum/s...ead.php?t=9484
It does sound like the focuser is rather poor. The weight of a binoviewer might be too much.