Originally Posted by
guachi
There's no indication this ride is some kind of race or even pretends to be a race. There are no timed segments or any indication there are pace lines of any kind.
In one picture from the event there is someone with aero bars in the picture.
Also, since you can leave when you want in the first hour you can do so without being stuck in a group.
So I'm hopeful I can use aero bars (though I'll have to check to be sure)
That's good. I hope you have a good ride. However, I guarantee you that there will be pace lines, even though it is not a race. That's how people ride in groups because it greatly reduces the required effort.
Pace lines and tight groups of riders develop in these large events and you may have to actively avoid them. That's true whether there is a mass start or, as you describe, a staggered start. You catch up to a group or a group catches up to you, and you have to make the decision to separate yourself. That can be hard when sticking with the group makes the going easier.
Also, if your goal with the aero bars is increased speed, you may consider that being in a pace line without aero bars would almost certainly result in a faster century than going alone with them.
But if you don't have experience in pace lines, doing it in a disorganized group of strangers is not a good way to start.
Finally, as a general rule, doing something new and different on a long ride (changing your bike, changing your position, changing your kit, changing your nutrition, etc.) is usually a bad idea. Make sure that you get in some practice rides with your new setup before you go for the long ride.