Doesn't sound like there is an easy way to control polarity when slaving the FTA receiver. It looks like the 4DTV receiver will have to be on to move the satellite to the correct azimuth and polarity. Then switch over to the FTA receiver to watch the target channel. Not something my wife is likely to pick up.
I am interested in picking up the DVB programming in C-band in addition to what's on the Ku band. That keeps me from being able to use a smaller offset dish. I think I'll put the system in as you guys suggest. If I like the C-band DVB channels, I'll put up another big dish dedicated to the FTA receiver. If I do that, will I have to purchase a dish mover or do the FTA receiver's have that capability?