Not an answer, rather just a thought for your pursuit.. I found it impossible to find and lock on to a digitally modulated carrier at first, with the 1.2m Andrews. What eventually saved the effort is tuning the dish and LNB using an analog channel displayed on an analog tube television. Were I to attempt it again, I would likely use this method.
Admittedly, it has some pretty restrictive limitations. Not the least of which is you need an analog receiver, and the bird you'd like to tune must have an analog signal.