Since you have an analog receiver hooked up - it might be much easier to hunt for the remaining 2 or 3 analog
C band stations that are in the clear to see if your dish is aimed right.
Then you'll know at least you are on the arc.
There should be ARTS, and a couple religious stations still on analog.
But since I haven't had a C band dish up for a while since my HH180 motor broke in half - maybe one of the other guys still on C band will chime in.
As far as the Geosat - yes you will use the FTA receiver to electronically switch H and V - it uses the 13 and 18v to do that.
The "power" to LNBF is normally always set to "on" so thats a set it and forget it.
You might want to investigate getting a
Vbox to move your dish.
Theres nothing wrong with what you are doing but the Vbox is a cleaner method when you move to an all digital FTA setup controlling a big dish.
Good luck .
Let us all know how you progress. We all like to read posts good and bad results.