1a. If I'm answering a CQ, I will typically use a 1x4 -- my standard 1x1 macro followed by an "ID 3" macro.
1b. If I'm replying to someone who has responded to my CQ, I will use a 1x1 unless he hasn't copied my call correctly. Then I'd use a 1x4 as above. And I won't start the QSO itself until he copies my call correctly.
1c. During the QSO, it's only a 1x1. Anything else is a waste of time.
2. IMD and SNR are useless IMO. The way the software calculates IMD it's not correct unless the SNR is very high. And SNR is only useful to the receiving station, not the transmitter. So please do not put/leave them in your macros.