Yeah, I didn't like my flea either.

That headlight is about as light as you will get. The small Dart is about 40 grams, but 70 is very light.

I have a full size light at 150 grams. Mounted center on the helmet I don't have any problems (and I'm not as young as you, lol). I can tell it is there, but it doesn't cause any issues. I think mounting center is your best bet.

You could always get one with a small reflector and a remote battery in a backpack, but that is overkill. I find on commuting and street riding, a handle bar works OK, but obviously you get much more visibility with a helmet light. Personally, I use both bar and helmet.