i have a 50 on the walker. it's a steep as hell track bike, and definitely twitchy, even with a conventional stem, but i actually find the additional rotational mass of the aerospoke to be somewhat stabilizing, so the two sort of cancel each other out.
so believe it or not having what is decried as a just-for-looks front wheel and a ridiculously short and unsuitable stem actually has a beneficial effect on the bike's ride. not to mention it puts the bars right where i want them, and leaves my center of gravity somewhat rearward in relation to the bike, which was my intent.
it makes for a fast and very maneuverable bike, and an upright and high rider stance, plus the ability to lift the front end readily — the perfect set-up for nyc's ****ty road surfaces and dense traffic.