It will work, but will be more comfortable with a counterweight. I love 15's, and have some good memories rocking them. A lot of people don't like the ABC, but I have found that there are a lot of situations where you don't have time to adjust gain and/or that is not where your mind is at.
If you haven't already bought the helmet, I would look at the Team Wendy LTP. It is more stable in my opinion, and that seems to be the same for a lot of people, but I would imagine the shape of your nugget has something to do with that.
I don't like running lead weights. It is weight that doesn't have a secondary purpose. In my old unit, we ran a dual mag pouch with two G19 mags. You don't expect to use them, and they are EXTRA, you still run your normal mags on your warbelt/rig, but at least they have a purpose. It is more common to run batteries as a counter weight, but I find that it takes a lot of batteries to get the weight I want, then they are hard to get to if you are not flexible, like me. I run the mag pouches upside down, so I can get to them if need be without removing the helmet. For the record, I've never had to strip a mag out off the back of my helmet in a sporty situation, so it may be moot.