125 or 250 two stroke?

So my 250f is getting pretty expensive. Rebuilds and valve adjustments are a pain in the ass, as well as monthly payments (I bought it new 2 years ago) 

Im wondering if I should go for a 125 or 250 two stroke. I am 6 foot tall and 165 lbs. am I too big to be competitive on a 125? I race 60% moto, 40% hare scrambles. Im a good all around rider, and i'm pretty fast on the track. Im afraid that the 250 two stroke might be a bit much for me in the woods or on slippery surfaces