one from column A; one from column B . . .
That pair of LNBs on the right of your picture are bandstacked (DishPro in the Dish world) and do 121º FSS/linear on the right, with 119º circular on the left.
Putting two FSS LNBs on that dual plumbing hardware apparently won't work.
So, if you get the tall horn of the 121º LNB at the focal point of the dish, you might be able to pick up some stronger linear FTA signals.
Your receiver will need to be adjusted to accommodate that type of LNB.
The LNB to the far left in your picture, is standard bandstacked (DishPro) circular LNB, and can be used for NASA & Angel One on 119º, if located correctly.
Aiming the linear LNB at one bird will be the priority.
edit: and you'll have to skew the entire dish, because there is no provision for skewing the LNB.
If the dish has enough beam width to place the circular LNB to get a signal, that's a bonus.
As long as you choose a circular bird not too far off the boresite, I'm betting you'll have good luck.
edit: here's what one of our members, NetBuilder, managed to get
on his dish (note the size).
That 6x8 switch is all but useless in general, and more so with the bandstacked LNBs you're using.
Not to say there isn't any sort of imaginative trick you could do with it, but in general, it's
not the right stuff.
edit: you could use any diseqc switch, or maybe a Dish DP-34.
I will award two points for creativity and imagination!

Your dish size:
22.5 in. x 32.5 in.