OK, I've been trying to keep up with the many of these discussion out there, but I haven't yet seen this in particular addressed. I got most of what I need from Ted here:

http://www.avsforum.com/avs-vb/showthread.php?p=15256090#post15256090

HOWEVER, over the weekend actually trying to start this process I came up a few questions not yet addressed, at least that I could find.

I'm installing RSIC EXT-04 parallel to joists. Joists are 12" OC. So, I run every other joist acccording to Ted's direction in thread above (Thanks again, Ted!).

BUT, the ceiling at that point is only 9' wide. So, If I put a clip 6" in, then at 48" then at 6" in at the other end end, that leaves three clips, per row at 24" OC. All of the diagrams show a staggered approach. This would align all of the clips in that part of the room at 6" - 48" - 6".

Is that a problem? Are TWO enough in a 9' row, or do I need to go to four (or FIVE) to offset?

In that instance I wouldn't worry about the staggering. Come off wall or soffit 3"-6". Next clip is dead center at 54".

No problems.

Ted -

Thanks! Think I can make some good progress now.

I guess I should have just PM'd you. I knew one of you experts would come through.