I thought it was only Big Aeroplanes that had rotate speeds. My technique in singles is an early check in the take off run that the ASI is alive and increasing, then it's eyes out the window and when she's ready to fly
There is definitely a rotate speed for lots of light aircraft, including the PA28.
In the aircraft that I've flown, I've tended to use your technique of feeling when she's ready to fly in tail-draggers, but a positive rotation at a set speed in tricycles. My instructor believes that the PA28 needs to be positively rotated, more than many other tricycles even - but, despite having done my PPL on the PA28, the fact that I haven't flown them extensively for quite a while means that subconciously I'm falling back on my tail-wheel experience when I can't see the ASI, and feeling when to rotate - and as a result I always try to lift the nose too early and loose a bit of control. Not sure if he's right or not - but I'll try looking over to the ASI next time, and we'll see!
FFF
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