An update:
[TL;DR: I went to early resolution, was offered a lesser charge with a much lower fine without any real discussion, and ended up getting fully off since the ticket hadn't been registered]
I filed for an early resolution meeting, figured since (1) I knew I was guilty and (2) there were no demerit points on the line, I may as well see what they would offer me.
I was told to report to the Centre Avenue courthouse in Toronto, appointment was for 8:45, the courthouse doors opened at 8:30. All the assembled people with the same time slot (maybe two dozen?) waited in the foyer waiting area, there was no procedure to sign in or register. The prosecutor arrived at 8:50, and asked everyone to just line up. If you're in a hurry I recommend sitting near to the door of the cubby/office listed on your appointment (e.g. SER1) to get near the front. Each meeting took a few minutes tops.
On my turn, I entered, said good morning and gave my info. The prosecutor looked up my file, said I was charged with running a red. I said yes, I proceeded before green on a bicycle, I know I shouldn't have, and was sorry. He gave me a little speech about how rules are rules, and what I did was wrong and dangerous. I was prepared to argue that last part, I had prepared some diagrams and had google earth printouts, but didn't get a chance. He asked me if I was looking to take a deal, and I said maybe, it depends. Without any further discussion, or even the chance for me to present any arguments, he offered me a lesser charge 144(5) Improper Stop, with a $100 dollar fine (down from $325). I asked him if this would show up on my drivers abstract for insurance, he said he couldn't be sure but that this would mean no points. I hemmed and hawed, he said it was the best that he could offer, so I accepted. He wrote it down on my printout of the early resolution meeting notice, and told me to go down the hall to Courtroom C2.
In contrast to the long line for the prosecutor, there was no wait at all at C2. The previous case was just wrapping up as I came in. I dropped my paper in the marked filing tray, and sat. Almost right away I was called to come up. A different prosecutor was dealing with this part of the process, he read out, from the notes that his buddy had made, that we were making a joint submission to an altered charge. The Justice asked me if I was pleading guilty and I said yes. Before she could say anything else the clerk (I think it was the clerk, sitting between where the prosecutor was standing and the Justice's bench) stood up and said that there was an error on the ticket, as it had not been registered. The justice then said she could not accept my plea, and that I was free to go. I said thank-you your worship and booked it out of there.