Not sure why lightweight is a major factor for you?. I bought a pair of gore tex lined boots from britishmilitarysurplus.co.uk, grade 1 used, £30. Had them for about 18 months now, got through last winter just fine. Not very light, and a bit warm in the summer, but comfy, hard wearing and cheap, so ticks all my boxes!. Actually most of my 'uniform' came from the same place. Navy work trousers with RAF (blue grey) jumpers, all were cheap as chips. The trousers, like the boots, are a bit heavy, but obviously hardwearing and the jumpers are extremely cosy, so much so, it needs to be properly cold to work in them (otherwise, t-shirt and bodywarmer)