Yeah, I pretty much agree with the front upper vent not working that well. I have used the Stephensons in some really wet conditions in the NE part of the USA (including one ten day trip that rained solidly for 3 days and every day we were out paddling.) The vent itself is simply too small and is the ONLY high vent in the entire tent. I believe it needs more, high ventilation to provide a proper chimney effect. So, except in winds greater than 30mph, it really doesn't work that well. Most of the time, we easily find some sort of wind shelter, often a grove of trees, a larger rock or bushes, to hide the tent from major winds. I have asked the wife to put a second vent in below the first. The style seems good. We *did* have a minor leak at the base of the vent (the bottom of the "V".) I seam sealed it again and it went away. This was the only downside to the vent design.
The tension does not appear to be a problem. In fact, it seems to accur as a product of the angle to the ground. So, the three basic stakes are enough to do the job. In higher winds, four others are needed, at each hoop end, of course. I also use 16" guy lines on the window awnings leaving about a bit of vent clearence on the bottom. These also supply additional stake points for the canopy leaving a total of 11 staking(pegging) points on the tent. It does NOT move.