Lother Walter barrel selection

 So I'm going to order a LW barrel after the holiday and need some suggestions on which one for slugs.

My current LW barrel is choked and shoots jsb redesigns perfectly but havent found a slug that does good enough in it. I'm going to order a no choke blank and have it machined, so my question is what twist rate might do better with slugs shooting .22 around 950 fps 16 or 17.7?