Two problems making a 311 into a release.. First.. the sear is so soft.. you need to rebend them on a regular basis to keep them working.. That change alone makes it impractical.. and second.. the hammers are burried deep inside the frame..so getting a "hook" on them is quite difficult.. While I've converted many to single trigger..and they work well.. the insides are basically.. cheap crap.. I'm not sure what the up side would be..
I shoot a release, but went to a SxS sporting clays shoot and found I could shoot a double trigger. It's almost impossible for me to shoot a single pull trigger for trap or sporting clays.
I think the fact that it was so different, I didn't accidentally "set" the trigger a couple of times like I would have done with a single trigger.