Glen,
Optically the Es is good but there is not much thread holding the dovetail. I recently bought a 2nd hand es and the vendor did not tell me the dovetail was loose due to either insufficient thread or he cross threaded it so it was not firm.
I purchased the guang sheng 90mm clamps from Andrews Communications.
, fits perfectly, and adapted the es dovetail to fit. It is now solid as a rock.
George