unpopular suggestion
Got nothing. Very frustrating.
Also, I am trying to attach the lnbf next to and/or above my centered Ku lnbf on my offset dish.
Can't get a thing and having trouble lining up the dual c/ku lnbf (only using the c-band portion of this guy).
Anyone have any suggestions?
Yes, until you get C-band working, give up Ku on this dish.
I'm sure you have other Ku dishes and LNBs.
Buy (not sure this one would fit) or build a mount to put the C-band LNB centered at the focus of the dish.
Locating that position should be apparent from inspection if you have a Ku LNB mounted normally.
I know I've built mounts to put "the wrong stuff" at the focus, and been very close.
... and once you think you have the LNBf mounted and aimed, don't be shy about moving it toward and away from the dish, to optimize focus.
It may well focus a little closer than your Ku LNB did.
And of course, the skew is a major concern.
I'm sure you have that under control, but it's worth reviewing.
Here are
pictures and words for both the CK-1 and BSC-621 LNBfs.