Keep in mind that Simmershield designed there system to be fuel efficient. To me, the inlet and exhaust pathways look fairly restrictive. Note that Simmershield states the following:
Windproof is quite a claim, and we won’t make it. No adventure stove works very well on an exposed ridgeline in a howling gale.
SimmerShield performs better in the wind that a lot of other options, but for best performance you should still try your best to shelter it behind a windbreak (a shrub, log, rock, pack, your body, etc.) when possible.
They also mention that the stove should only be operated at a low flame setting.