So, I just thought I'd share with everyone my jubilation.
I've been practicing a little every morning and evening for 3 weeks and I can now group about 7" at 18yds with my magnus stingers on. Thanks for everyone's help in troubleshooting the tuning process!!
I know there can be quite a bit of controversy over who makes the best bows etc. But I do have to say this, I told the guys at Black Widow the specs of the SAIII I bought off the internet, the type of string on it, which BH's I wanted to shoot, and they put me dead on with the arrow I needed. My bare shaft now groups very well after adding 5 additional grains up front and has no kick. I guess the real test comes when I start going out to longer ranges.
Dave