Trevor and David,

I tried your suggestions.

Loosening the Trigger Tang Screw has 2 turns allows the rear trigger to clear the sear and the safety blocks both triggers. With the safety in the full forward and rear ward, the hammers release normally.
This was repeatedly proven after 15 operations using snap caps.
My plan is to remove the trigger plate and insert a 0.030" shim under the trigger plate at the Trigger Tang Screw.
Thank you for your help.