Balclavas need to be resized so that the helmet straps don't clip through the masks.
I looked into this and to be honest, I don't believe it can be done in a generic way. If I tighten the facewear, it will start clipping through the head, and if I loosen the straps on the helmet they look like they stand out too much, there is too much of a gap in it.
TBH, I think the only way this can work is make a specific helmet with the facewear and adjust that. Anything else will not work in a generic fashion.