I use shear end plates from time to time. To ensure enough rotational flexibility, I check the AISC Manual (16th) Equation 9-52.
Like in your double and single angle figures above, the idea is to ensure the end plate can bend out of plane to allow most of the simply supported beam end rotation develop and avoid a beam end moment.
It's not clear to me from the OP's question whether this is a shear or moment connection. He or she seems to have gone poof, so I guess that's that. LOL