I wouldn't recommend the pop up tents, although they may be just about waterproof enough, they haven't got the strength for the conditions you're likely to encounter. It's not much fun trying to sleep when the wind blows the fabric of the tent down onto your face and you get soaked from the moisture on the surface.
Ridge tents (the triangular ones) aren't the only ones, you can also use dome, half-dome, tunnel, or geodesic designs. A 2-3 man tent should be about the right size, remember you can split the weight between the people sleeping in it so if you have a bigger tent you've got more people that can carry it but chances are each section will be heavier. Domes give a good amount of space and are pretty stable, tunnels have more room but need to be pitched with the back of the tent into the wind, geodesics you can pretty much just chuck up and let the gods decide where the wind comes from. Try and go for a two skinned (inner and outer) design, as that cuts down on the amount of condensation that will drip onto you inside it.
For reference, I carry my own tent but I'm more of the assessor side of things, and it's a Terra Nova Ultra Quasar, so only wieghs 3.1 kilos all in. Argos do a semi-geo
that weighs about 5 kg and can be split up, or the Blacks own brand ones are pretty good. If they quote waterproofness or hydrostatic head, look for 2 m mimimum, pref more than 5 m.