In case it helps anyone else waiting in terms of waiting times etc, my timeline for querying (so far, literary fiction) is going like this:
I sent out queries in groups of two or three at a time between January 12th and 29th.
One I sent on Jan 12th got a no on Feb 24th.
One sent on Jan 16th -- request for a full on Jan 26th. Nothing back on that yet.
Those I sent on Jan 20th got a no on Jan 26th and another on Jan 28th.
One I sent on Jan 27th got a request for a full on Jan 29th.
One I sent on Jan 29th got an extremely nice no via Query Tracker saying that if I didn't place this, she'd be interested in my next one (which I'd mentioned in my letter) on Feb 4th.
One I sent on Jan 15th got a request for a full on Feb 3rd, and ended in an offer on Feb 11th.
After I had the offer, I nudged everyone else who had the full or who hadn't yet said no, attaching the full MS for those who didn't have it, resulting, so far, in one more offer, five who have acknowledged and say they will get back to me before my deadline, and three extremely nice, complimentary nos, plus two standard 'I didn't feel strongly enough about the material' nos.
Three agents have not replied at all (so far), and one who asked for the full on Jan 26th has not responded to my offer of representation nudge.
One of the things that occurs to me is that some agents, when you query them, give in their automatic acknowledgement mail a separate, individual email address to update them with offers of representation on, while others don't, so any updates quite possibly don't reach them for ages, as they just go into the standard submissions mailbox.
One agency had an unusual arrangement (well, unusual to me) in that they had an (extremely nice) reader whose job was to read all submissions to the entire agency. You could specify which agent you were targeting, but the reader would only pass it on if she thought it would be of interest to them.
One of the agents I've spoken to said that this year she has only taken on a single new client, and that was via a personal recommendation, not from her inbox. But, looking on the bright side, she does read everything sent to her in that inbox.