I have my 1m winegard dish (note that it is 1m x 1.1m in size, and not the 0.9m x 1.0m in size... the effective size is 1m due to the offset) parked on G10r for most of my unattended recordings, and 11720 has been having some issues. The signal does drop out sometimes and is very inconsistant. I use a Quad 0.3 LNBF and have tried re-peaking the dish just this weekend. The other transponders are a lot stronger in strength lately, so I don't think that it is just the dish satellite interference that is the problem. The 1m dish has a narrow enough pattern that the dish satellite should not be an issue. The issue is that that one transponder is currently so low in power that any weather (at either end) makes a big difference. I would say for reliability, a 1.2m dish (minimum) should be used unless the power levels return to what the were. If you can live with the 11720 issues, then a 1m dish works great for the rest of the transponders. I would say the majority of the time, the 1m dish works greats, but the picture will breakup sometimes over a week.
Before the current issues, the transponder 11720 would be almost as strong as the other transponders. I would say about 98% of what the others were. With my Digiwave 7000, all the transponders would peak out at 99% quality, but 11720 just took a little finer adjustments in peaking the dish.