Hector,
Yes that is a two port orthomode feed with single polarity lnb's. You can only look at one polarity at a time, then connect to the other. Leave the Birdog set to Horz for both.
The dish is wild. Never seen one of those. Don't know why it would be so touchy. C-band should let you move the dish an inch or so. Just do all moves slowly in small increments.
EDIT:
I see one thing that might be a problem. Azteca looks like it is DVB-S2. I don't know that a Birdog can tune that. Try for AMG TV, connect your Birdog to the horz lnb, key in 3991 Horz, SR 9983 which is DVB-S. Peak your dish on this signal then connect your down link cable to the vertical lnb, go inside and tune in Azteca on your receiver.