That clamp was specifically designed for the GSP 90cm dish and has been installed on approx. 7-8k systems. It is aimed where it should be....
When using the dual 4 degree clamp, calculate the dish elevation/azimuth and dual clamp skew settings for the 123w satellite. Align each of the bullet's LNBF centering line with the arrow embossed on the top of the clamp and start with the face of the LNBF moved towards the dish 3/4" measured from the forward clamp edge.
Skew the clamp to the 123w calculated setting. Attach coax to the right LNBF (standing in front of the dish) and place the STB on satellite 125w. Adjust the dish elevation and azimuth to optimize the PBS signal quality.
Power down the STB and install the switch and jumpers to LNBFs and STB. Repower the STB and program the switch. Check 121w for optimized signal quality. Slide left LNBF towards/away from reflector to optimize.
Check 125w again for optimized signal quality. Slide left LNBF towards/away from reflector to optimize.
When both satellites are optimized, gently push on the edge of the reflector East/West/Up/Down and observe if the dish aiming can be optimized.
Finally, make slight skew adjustments to each LNBF to peak the Signal Quality reading.
Hope this helps!