This is probably the wrong thing to do, and I’m sure that will be pointed out to me, but my Schuberth 3/4 was a great fit except at the forehead.....and it was expensive and brought in from overseas, so I couldn’t ship it back easily. I carefully released the material covering, shaved maybe 1/16” off the forehead styrofoam using a small flexible box cutter, and reapplied the material. That was 4 years ago and it, along with the Shoei J-Cruise are the most comfortable helmets I own. Pete
I use heat, like with a soldering iron, to selectively melt the foam in places it's too tight.