I have been at this satellite lark for coming up to three decades now, more if you include the anticipation of reading the reports in
Television magazine, etc.
I am still amused that many people in Spain particularly are failing to understand some of the basics of big dish use. I am not criticizing you here, I mean the kind of installer who turns up on a horse wearing a large stetson (I suppose it keeps the sun off!).
Read my reply on another astra thread, on receiving Astra 2E on a 2.4m dish post #209
http://www.satellites.co.uk/forums/threads/astra-2e-western-europe-reports.159945/page-11
If they are going to space out the satellites a bit more it will create problems with big dishes because of the narrow beamwidth.
If they are more than 0.2 degrees apart it may be necessary to have two large dishes to receive them consistently with enough gain to ensure reception at all times.
Remember that the satellites wander around in their 'box' in the sky and you have to take that into account.
Atmospheric electrical thermal noise and man made background electrical noise and aliens trying to contact us from outer space on a bad choice of frequencies 
is something we can't do much about except try to drown it out with a big dish and to ensure proper shielding in the cables (removal of the foil and making sure the braid wire is evenly distributed around the cable before putting the F connector on, if its not a crimped f connector a decent amount of self amalgamating tape and a drip loop will stop it sliding out under its own pressure).
The principle of beamwidth selectivity is fundamental to using a big dish. And so is the satellites annoying tendency to wander. Thats why a big dish (from 3m to 6m) in a professional dish farm can remotely adjust for inclination.
What I am saying is that what few people seem to realize, despite installing these dishes for years, is that if you want to get weak signals from co-sited satellites with big dishes there is a point where you have to use two or more big dishes due to the narrow beamwidth and the need to provide enough gain to ensure constant reception (and so avoid domestic violence).
In my view this effect means that once you go over about 1.5m then you are better off assuming a 0.1 degree granularity in KU band no matter what the published specification says because there are so many factors that plague weak signals.
Recall that the mid band circa 11.5GHz specification for 3dB beamwidth at 1.5m is around 1.2, at 1.8m its 1.0, at 2.7m its down to a narrow 0.65 degrees. With my ancient 2m dish the polar mount has a massive threaded bar easily four times as thick as the ones they use today. But even with that room to manoeuvre on weak signals selectivity is surprisingly sharp.
So the unfortunate truth is that once you need to use dishes in the 1.8m to 2.7m bracket and above then if you really want reliable 24/7 reception which I assume is the aim then you have to do what the professionals do and that is to use two big dishes.
If you want 24/7 reception there is no way around that as you cannot ensure enough gain and good CNR and MER any other way. (MER measures how much the weak signal has been mangled on its way to the receiver).
Also bear in mind the advice I keep giving and that is to find out what dish size people use and try to use the next size up. I use an 80cm here for 28.2e when I could use a 60cm and it means the signal never cuts out no matter the weather (google
huricane bawbag) and I don't get moaned at.
I don't know what prices are like in Spain but I recall the large Channel Master (now Raven) dishes being two to three times the cost of prime focus metal dishes like the Famaval. I would be inclined to buy two big Famaval dishes if I was in Spain. With the mostly calm and dry climate of Spain I really don't see any point in getting a Channel Master dish except for professional use. Even if I did want a GRP dish a Laminas is cheaper and just as good.
Looking again at the Famaval catalogue I see the biggest offset they make is 130cm. All Laminas dishes are offset, but they are all GRP.
Sods law means once you put up two big dishes, the channels will be combined on one satellite. You sell your extra big dish at an annoyingly low price then six months later they split the wanted channels over two satellites 0.2 degrees apart again . . .
All in all its a kick up the Balearics.
