The bulbs you are using have a buck/boost regulator built into the lamp, that is how they
can run off such a wide voltage range. Normally, white LEDs require somewhere between 3.2 to 3.6
volts to reach full brightness. The built in regulator allows you to get around this limitation, at the
expense of loss of efficiency (pulls a bit more current).
If you want the headlight's reflector to do anything you could try modifying it to allow you to mount
the LED bulb farther back into the reflector, it won't ever look the same as it would with an incandescent bulb,
however, because the LED has a 120 deg. beam pattern, and an incandescent bulb is effectively 360 deg.
If you intend to use it for riding at night there are a few things that might make it work better, 30 Lumens
isn't much light, though.
Have Fun!