Standing Undergrip Dislocate with Weighted Ba

I am about a month into Standing Undergrip Dislocate with Weighted Bar. The exercise is challenging but I am making good headway with shoulder mobility. Where I am struggling is with wrist/forearm/elbow mobility at the bottom of the movement when the bar is in front of you. Any suggestions?

Probably you need to pass more time on the stretching exercise at the beginning of the handstand series,  especially the one that stretched the wrists extensor that it WRS #2.