Hey lumpkin666,
I have read in many places here and on other forums where they advocate the smaller size holes for Ku. They use the lead from a wooden pencil as the guidelines.
I have also read that if the whole #2 wooden pencil would not pass through the hole, that was the largest the holes could be.
I wondered about the conflicting stories until I put up my Birdview perforated aluminum dish. The holes in it will almost allow a #2 wooden pencil to pass through, but not quite.
The Birdview gets the best Ku reception I have ever had including P* dishes dedicated to Ku only.
As long as the holes will not allow a #2 pencil to pass through, they are small enough.
The next thing to look for is imperfections in the dish, warped, focal distance set correctly, f/d ratio, and skew. Feed-horn centered on the dish and parallel with the plate in the middle.
Also, I have read since yesterday that the BSC621 has a 22Khz switch for changing between C and Ku. The 621-2 has the built in diseqc switch. I would double check that information.
I just got off the phone with a dealer here in MO who sells the BSC621, and he says that he has customers using it with 4DTV and getting good results.
If I don't find a used Co-Rotor soon, I will be using either the BSC621 or the Geosat C/Ku LNBF.