The "not easy to ND" is kind of an odd requirement. That's kinda of like buying a supercar with a reduced ability for speed and handling. You buy a gun to shoot, and since an ND primarily translates to pulling the trigger when you shouldn't have, if it's hard to ND, it's hard to shoot. So I'm not really sure what you mean.
I just thought about that this morning. I know I said that this person would be following the basic firearm safety, so trigger discipline would make the accidental ND unlikely. I guess I'm referring to guns that require you to manually lower the hammer, tend to fire out of battery (particularly if you do something "wrong") slam fire, or what have you.
I would say firing a DA/SA in single action is not any harder than just a SA, so I guess I don't know what YOU mean about it being harder to shoot if it's harder to ND