So i recently did a hack n tap sye and i am still getting vibes from the rear DS. I understand that the driveshaft needs to have no angle at the yoke when you are using a front shaft for the rear. I know i need to shim the rear however im having a hard time figuring out how much it needs. When i measure the difference in angle between the yoke on the diff and the end of the shaft i get something like 18 degrees. 18 degrees of shim is plain stupid and just looking at it that cant be right. Is there something im missing here? Ive included a picture below.