The t0case spacers lower the top end of the driveshaft, so that can help a bit. T-case flange normally points down a few degrees, the spacers also drop that angle a bit more. You could be at the point the shaft angle is too steep to ever run smooth. Mine hit that point somewhere between 12 and 15 degrees overall operating angle. Even with everything perfect (angles, phasing, balance) it would still vibrate.

But first, follow the instructions on my page, if you could not follow the link above, here it is directly.

In summary, tape measure across the top and bottom of the driveshaft, record the difference in flange-flange distances, every 1/16" off is 0.9 degrees. You want to end up with the bottom distance about 1/16" - 1/8" more than the top flange to flange distance.