A 1.8 meter dish is what I would like to have which I believe is 6ft. But I do not want the large dish in the yard the wife will not allow it. But you will find that a 6ft dish has its advantages. For instance if it is true that they moved the Soundtrack Channel to the other transponder as Iceberg has noted, I think the 1.2 meter dish I have may not pick that transponder up, but a 1.8 meter should?
A 1.2 meter dish works great for a good deal of the channels with certain formats, symbol rates and FECs, but does not get them all. It depends on what your viewing needs are and your location. But be careful as a lot of the FTA channels on all bands have a tendency to move to differnt transponders that maybe weak and a 1.2 meter dish maynot be able to receive them with enough quality level for good reception.
Just for an example; White Springs TV a KU linear channel recently moved to a different transponder as did FSSN on 91W. So what a certain dish can get for channels one day for KU and Cband may not be true the next.
A small 1.2 meter dish is a great dish to start wth, experiment and get many quality channels. The 6ft dish will improve reception greatly and allow for expanded formats. Larger prime focus 10ft diameter really gets you playing with C-Band, it all depends apon your viewing needs and what you have for a receiver.
Even though I can receive channels from almost all the C-Band sats, I mostly watch 4 channels on 72W Nasa, This TV is on 87W which also can be found on 99W, a few channels I will not mention on 91W for a good reason and some sports channels there, 95W carrys some horse racing and a few other feeds, 97W has a few good channels including KCSG TV, 99W has a dozen channels worth viewing the network channels as well as WHT, on ocassion I get some channels on 107 Anik but come and go, 121W has STO, Sportsmans and The Soundtrack channel or at least it used to have the Soundtrack Channel on a transponder that my 1.2 meter dish could get, and there are a few channels for Alaska I watch on occasion can't remember which sat 131-33-35-37 or 139W they are on, sometimes a movie channel goes in the clear on one of those sats for awhile but think it is an encryption error. But when I add C-band on the 1.2 meter dish it compliments the KU off the 76cm dish to offer me a nice package of valuable channels to view.
If there is a specific channel for standard DVB format C-band that you are curious about and want to know if my setup can receive, I would be glad to let you know if I can get it in without pixelation and can note the signal quality. But you have to remeber I will be using a Coolsat 5000 receiver for this. Should hook up my Pansat 2700 and see how it compares, will try this next time I have time to play around with the dish.