One other point of interest is that thick edges increase the rotational resistance. I have heard others say the opposite.
This is one of those statements that is endlessly repeated as "fact" as though it makes a difference.
With two bats of the same weight, the additional mass that is moved to the edges by making them thicker is actually very small and is offset against the amount lost due to concaving near the spine. Both of these components of the mass have an effect on the torque "generated" by the mass of the bat.
When you consider that the key aspect of the force implied by a cricket ball on the edge area of a bat is the rate of change of velocity of that cricket ball, of which velocity is the key part, and that the change in the inertia generated by increasing the edge size is something in the region of 0.05 times, you start to see that the reality is very different.
Yes it does "increase the resistance to twisting", but it does so by such a small margin that it
makes no difference. It is purely marketing hearsay bs.
Better ways to stop the bat twisting are to use an oval handle and hit the ball out of the middle of the bat.