He needs the gain of the larger dish because he is so far off the boresight and the EIRP is low. I used to correspond with someone who was operating a pirate cable TV service in Venezuela, and he used to have to use dishes that were ten to twelve feet in diameter, and the problem he ran into was that at 101 degrees, there were three satellites operating in that "slot" a few tenths of a degree apart, and he actually had to target two of them with one dish and one with the other.
The larger dishes are also vulnerable to the "migration" effects of the satellite as it makes its daily drift through its figure eight pattern in the sky. You might need to learn at what time the satellites are at the crossing point of the figure eight and peak it at that time.
Last I knew, DirecTV would not allow United States multiple dwelling system operators to use dishes larger than 4 feet because of the tradeoff that was incurred by actually losing signal from one satellite because the beamwidth of such a large dish was so tight.
I have not had any reports regarding to reception of Ka band signals outside of the continental United States. I believe that the EIRP footprint tapers off more sharply at those higher frequencies, and someone desperate to get those signals in Honduras might need separate dishes for 99 and 103 with the SWM feedhorn deliberately mispositioned to the prime focal point.