Likewise, I think this thread got pulled away from the OP's intentions by a bit of fixie mania introduced by others. Look, the situation is pretty much as I said - if you are strong enough to be competitive on gears in D grade or higher then you will be fine in E on SS (with the right ratio of course - you may not know what that is until after each race...)
Things to watch for or keep in mind on the day:
1) if you see any riders talking towards the front of the pack, expect to see someone jump away in the next lap or two (so get near the front)
2) Stay away from the rear of the pack - no matter how comfortable it feels to be there in the straights, when the pace starts to go on you will need to kill yourself just to catch the back of the main pack again in each straight due to the concertina effect in each corner where you will slam the brakes back on. (so get near the front)
3) Nobody says you HAVE to work turns (no matter whether people in the race actually yell at you to go to the front). (So get near the front - but not in the wind)
4) From about 3 or 4 laps to go, there will be a number of hero attempts by people who may or may not have the strength to last even half a lap at that pace. Don't fall for it and chase them - let someone else. (So get near the front but don't do any work)
5) You may very well feel awesomely strong with 3 laps or so to go but DON'T attack unless you are really sure you can get away (see point 4). There are a lot of other guys around you that may be hiding their good legs and they will mow you down if you don't get a really good break really fast.
6) Riders that are shouting are not necessarily strong - they could just be w@nkers so don't be afraid to hammer them.
7) Riders shouting to each other are not friends, riders talking to each other are not just friends, they are probably plotting against you (see point 1) so if you are reacting to one of those guys, always pay attention to what the other one is doing or you will be double teamed.
8) There will probably be a hero atack in first 2 laps. Pay attention to this one as if they are strong they could get away and make it stick. Also it could result in a counter attack that will be even more savage. Also, if people start jumping the gaps as individuals, pretty soon you will have to jump the gap by yourself too. (so stay near the front)
Summary: Save yourself and don't do anything you don't have to. Stay near the front and keep an eye on everybody even if they look really unfit.