Dish Net question

[Trailer Trash 2]

I need a question answered on the proper dish to use.
I have Dish Net system and it is the 500 type, that is supose to have the two round things that point at the dish one is 110 deg and the other is 119 deg. can I use the single type dish and if I need to see 119 I can just turn it.
or should I just get a newer type dish for the trailer? ( 500 type ) with the 2 round white things on it.
also where can I get one of these new dishes if I do decide to get one without having to buy another receiver.

Thanks TT2