The weight thing is interesting.
Ive always found that at the lower range of my weight I bowl slower and get injured more often.
At the mid-mid/high range I get through the crease with greater momentum and feel far stronger and balanced and bowl quicker.
I always thought that this was strange until I read Flintoff say exactly the same thing. He said he has to balance not being a fat guy with loosing too much weight and feeling weak.
We are not talking being skinny here, but natually big guys like myself and Flintoff need to carry a little extra weight than some others would believe in order to get through the crease and bowl fast.