There is a quick 'field test' to gauge headset tightness.

First, pick up the bike by the top tube, up near the head tube; if the wheel freely flops to one side or the other, it's not too tight.
Then, with the front wheel on the ground, apply front brake and 'rock' the bike forward and back, while feeling the headset/fork interface (top or bottom of the headset); there should be no fore-aft movement.

If both of these happen, your headset adjustment is pretty good.