ok twitchy is a result of the rake of the fork, the shorter the rake the twicher the bike making it easier to turn (extreme rake also causes this but for different reasons) the difference in short and long handle bars are leverage, the longer the bar the easier the turn, but larger radius of the handle bar, slows down the rate of turn to apparent bar movement, reverse that for narrow bars. try this grab your bars next to the stem and turn then at the end of the bar and turn.