I'm about your size, and also a trail/woods rider. Back when I was racing, I really liked 125's the best....... but that's kind of odd, I was in the minority. 125's are light, easily flickable, and really nice when braking or on the downhills, but require aggresive, think-ahead planning on the uphills. 250's.........longer top-end life, enough "lugability" you can be more lazy on the uphills, and the effect of more spinning-engine mass makes them a little less flickable, and you can feel the weight when braking, and in the corners. For me, when racing, the 125's were my weapon of choice. Now I like my 250......cuz I'm old and lazy.