12. Rfd1 is best. 12. a4 is premature, I think.
Should we be discussing our future plans or just our next move?
I think having a plan is important but if we discuss it openly, it will be impossible to surprise our opponent. Essentially he will always know what we are planning while we can only guess what he is planning.
I think it's obvious to both sides that the battle will take place on the queenside, with the half-open c- and d-files and Black's queenside pawns being key. A well-timed breakthrough here will be decisive, and neither side will be terribly surprised when it happens.
At first I liked 12. a4 the best to induce weaknesses if black plays 12..... b4. However as foxpup pointed out when we were discussing 10. Nc3 this is unlikely to happen. Instead black may just defend by developing his queen to b6 in which case I am not sure what we have accomplished.
Correct. We shouldn't put the question to b-pawn just yet. We should get our rooks in position first.
I would go with a4. After Qb6 I would recommend b3.
Why? There's no progress to be made with b3.
Rac4.
I would like to utilize the open c file immediately, rather than try opening the a file and then controlling it.
Don't you mean Rac1? Also, the c-file is only half-open (there's a black pawn on c5), and we can't open it by force. We should get behind the d-file with Rfd1.
I would like to change my vote from a4 to Rfd1. It sounds like you agree with me that a4 does not accomplish much if black just responds with Qb6