That Giro helmet on the L&M site looks more robust than the typical lightweight road type helmets.

When I commuted with my MTB helmet, (Specialized VICE) my helmet light, a Stella 150, worked great. The battery, mounted at the top back, and the light up front, did not faze the fit or balance of the helmet on my head one bit. This is probably because that helmet, and I would guess, most MTB style helmets, fit lower in the front and back, and the Vice extends lower on the sides around the ears too. So it is very stable on my head with the extra weight up top. I now use a Giro Saros for commuting, and while the Stella fits fine on it, the whole helmet has to be strapped real tight and still moves a bit with the extra top-heavy light. I can guess that a even lighter helmet could be even less stable feeling.

If I had a second chance to buy my commuter helmet again, I would buy another Vice as it works so much better with my Stella (even though it makes me look like a mushroom).