All: Here North of 60 we typically wear balaclavas, sometimes up to 3 at a time, from Aug. through June. Usually a thin thermax/wicking one in the mornings in the summer, then with 2 windproof pile ones for biking at -30°C, plus a neck tube (just a pile cylinder) to cover nose + pre-breathe through,worn inside a helmet with the air vents taped over, then off-bike a windproof nylon-faced pile dog mushing hat with ear flaps for below -30°C or high wind chills. I have even bought one oversized and then stuffed polyester batting into what was otherwise just a windproof pile hat.
Now, for all that, my best tip is to find a balaclava that you like, and see if you can somehow photocopy it!
You need to avoid seams on the forehead, and use flat-lock stitching. MEC.ca has one that comes close to this---my stuff is made-to-measure locally at Sportees:
Your balaclava neck bottom needs to be about 10cm longer in the front than in the back to cover your neck, and also to allow pulling the bottom of the face hole up over your nose below -10°C if you get caught out without a neck tube.
So, no forehead seams, flat-lock seams (minimal bulk), extra length in front, windproof polartec is substantially warmer for the same weight. I would only use Smartwool if you need fire-retardant properties.
We also wear ours rolled up as a watchcap every night all summer!
I hope this helps!