I have dual saddles (Vixen/ Losmandy) fitted to both my HEQ5 and NEQ6.
One is an ADM dual saddle and the other a Geoptik dual saddle.
Both are excellent and have given me no issues over the past five years.
http://www.admaccessories.com/DV_Series_Saddles.htm
http://www.apm-telescopes.de/en/moun...dovetails.html
The Geoptik on the NEQ6 holds the C11, spectroscope etc etc.