I think that you did a pretty good job on this pattern! Yes, there is some distortion on the sides, but it's hard to do something better. Perhaps the elongated circle on side could be corrected: looks like you created the pattern as a circle viewed from top, but since it's on slanted side, it's compressed and should look like a distorted ellipse viewed from top.
Otherwise...
The bottom of helmet is now BFC inverted! Anyway, there's some work to to there, you need to subpart the bottom and inner part of the helmet for other patterned version...
Otherwise...
The bottom of helmet is now BFC inverted! Anyway, there's some work to to there, you need to subpart the bottom and inner part of the helmet for other patterned version...